RETURN TO MAIN INDEX
SVM142-A
September, 2002
™
IDEALARC DC-655
For use with machine code number 10501 thru 10510
Safety Depends on You
Lincoln arc welding and cutting
equipment is designed and built
with safety in mind. However,
your overall safety can be
increased by proper installation
. . . and thoughtful operation on
your part. DO NOT INSTALL,
OPERATE OR REPAIR THIS
EQUIPMENT WITHOUT READ-
ING THIS MANUAL AND THE
SAFETY PRECAUTIONS CON-
TAINED THROUGHOUT. And,
most importantly, think before
you act and be careful.
SERVICE MANUAL
Copyright © 2002 Lincoln Global Inc.
• World's Leader in Welding and Cutting Products •
• Sales and Service through Subsidiaries and Distributors Worldwide •
Cleveland, Ohio 44117-1199 U.S.A. TEL: 216.481.8100 FAX: 216.486.1751 WEB SITE: www.lincolnelectric.com
Download from Www.Somanuals.com. All Manuals Search And Download.
ii
ii
SAFETY
ARC RAYS can burn.
ELECTRIC SHOCK can kill.
3.a. The electrode and work (or ground) circuits
are electrically “hot” when the welder is on.
Do not touch these “hot” parts with your bare
skin or wet clothing. Wear dry, hole-free
gloves to insulate hands.
4.a. Use a shield with the proper filter and cover
plates to protect your eyes from sparks and
the rays of the arc when welding or observing
open arc welding. Headshield and filter lens
should conform to ANSI Z87. I standards.
4.b. Use suitable clothing made from durable flame-resistant
material to protect your skin and that of your helpers from
the arc rays.
3.b. Insulate yourself from work and ground using dry insulation.
Make certain the insulation is large enough to cover your full
area of physical contact with work and ground.
4.c. Protect other nearby personnel with suitable, non-flammable
screening and/or warn them not to watch the arc nor expose
themselves to the arc rays or to hot spatter or metal.
In addition to the normal safety precautions, if welding
must be performed under electrically hazardous
conditions (in damp locations or while wearing wet
clothing; on metal structures such as floors, gratings or
scaffolds; when in cramped positions such as sitting,
kneeling or lying, if there is a high risk of unavoidable or
accidental contact with the workpiece or ground) use
the following equipment:
FUMES AND GASES
can be dangerous.
5.a. Welding may produce fumes and gases
hazardous to health. Avoid breathing these
• Semiautomatic DC Constant Voltage (Wire) Welder.
• DC Manual (Stick) Welder.
• AC Welder with Reduced Voltage Control.
fumes and gases.When welding, keep
your head out of the fume. Use enough
ventilation and/or exhaust at the arc to keep
3.c. In semiautomatic or automatic wire welding, the electrode,
electrode reel, welding head, nozzle or semiautomatic
welding gun are also electrically “hot”.
fumes and gases away from the breathing zone. When
welding with electrodes which require special
ventilation such as stainless or hard facing (see
instructions on container or MSDS) or on lead or
cadmium plated steel and other metals or coatings
which produce highly toxic fumes, keep exposure as
low as possible and below Threshold Limit Values (TLV)
using local exhaust or mechanical ventilation. In
confined spaces or in some circumstances, outdoors, a
respirator may be required. Additional precautions are
also required when welding on galvanized steel.
3.d. Always be sure the work cable makes a good electrical
connection with the metal being welded. The connection
should be as close as possible to the area being welded.
3.e. Ground the work or metal to be welded to a good electrical
(earth) ground.
3.f. Maintain the electrode holder, work clamp, welding cable and
welding machine in good, safe operating condition. Replace
damaged insulation.
5.b. Do not weld in locations near chlorinated hydrocarbon vapors
coming from degreasing, cleaning or spraying operations.
The heat and rays of the arc can react with solvent vapors to
form phosgene, a highly toxic gas, and other irritating
products.
3.g. Never dip the electrode in water for cooling.
3.h. Never simultaneously touch electrically “hot” parts of
electrode holders connected to two welders because voltage
between the two can be the total of the open circuit voltage
of both welders.
5.c. Shielding gases used for arc welding can displace air and
cause injury or death. Always use enough ventilation,
especially in confined areas, to insure breathing air is safe.
3.i. When working above floor level, use a safety belt to protect
yourself from a fall should you get a shock.
5.d. Read and understand the manufacturer’s instructions for this
equipment and the consumables to be used, including the
material safety data sheet (MSDS) and follow your
employer’s safety practices. MSDS forms are available from
your welding distributor or from the manufacturer.
3.j. Also see Items 6.c. and 8.
5.e. Also see item 1.b.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
iii
iii
SAFETY
WELDING SPARKS can
cause fire or explosion.
CYLINDER may explode
if damaged.
6.a. Remove fire hazards from the welding area.
If this is not possible, cover them to prevent
7.a. Use only compressed gas cylinders
containing the correct shielding gas for the
the welding sparks from starting a fire.
Remember that welding sparks and hot
materials from welding can easily go through small cracks
and openings to adjacent areas. Avoid welding near
hydraulic lines. Have a fire extinguisher readily available.
process used and properly operating
regulators designed for the gas and
pressure used. All hoses, fittings, etc. should be suitable for
the application and maintained in good condition.
7.b. Always keep cylinders in an upright position securely
chained to an undercarriage or fixed support.
6.b. Where compressed gases are to be used at the job site,
special precautions should be used to prevent hazardous
situations. Refer to “Safety in Welding and Cutting” (ANSI
Standard Z49.1) and the operating information for the
equipment being used.
7.c. Cylinders should be located:
•Away from areas where they may be struck or subjected to
physical damage.
6.c. When not welding, make certain no part of the electrode
circuit is touching the work or ground. Accidental contact can
cause overheating and create a fire hazard.
•A safe distance from arc welding or cutting operations and
any other source of heat, sparks, or flame.
7.d. Never allow the electrode, electrode holder or any other
electrically “hot” parts to touch a cylinder.
6.d. Do not heat, cut or weld tanks, drums or containers until the
proper steps have been taken to insure that such procedures
will not cause flammable or toxic vapors from substances
inside. They can cause an explosion even though they have
been “cleaned”. For information, purchase “Recommended
Safe Practices for the Preparation for Welding and Cutting of
Containers and Piping That Have Held Hazardous
Substances”, AWS F4.1 from the American Welding Society
(see address above).
7.e. Keep your head and face away from the cylinder valve outlet
when opening the cylinder valve.
7.f. Valve protection caps should always be in place and hand
tight except when the cylinder is in use or connected for
use.
7.g. Read and follow the instructions on compressed gas
cylinders, associated equipment, and CGA publication P-l,
“Precautions for Safe Handling of Compressed Gases in
Cylinders,” available from the Compressed Gas Association
1235 Jefferson Davis Highway, Arlington, VA 22202.
6.e. Vent hollow castings or containers before heating, cutting or
welding. They may explode.
6.f. Sparks and spatter are thrown from the welding arc. Wear oil
free protective garments such as leather gloves, heavy shirt,
cuffless trousers, high shoes and a cap over your hair. Wear
ear plugs when welding out of position or in confined places.
Always wear safety glasses with side shields when in a
welding area.
FOR ELECTRICALLY
powered equipment.
6.g. Connect the work cable to the work as close to the welding
area as practical. Work cables connected to the building
framework or other locations away from the welding area
increase the possibility of the welding current passing
through lifting chains, crane cables or other alternate circuits.
This can create fire hazards or overheat lifting chains or
cables until they fail.
8.a. Turn off input power using the disconnect
switch at the fuse box before working on
the equipment.
8.b. Install equipment in accordance with the U.S. National
Electrical Code, all local codes and the manufacturer’s
recommendations.
6.h. Also see item 1.c.
8.c. Ground the equipment in accordance with the U.S. National
Electrical Code and the manufacturer’s recommendations.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
iv
iv
SAFETY
7. Quand on ne soude pas, poser la pince à une endroit isolé
PRÉCAUTIONS DE SÛRETÉ
de la masse. Un court-circuit accidental peut provoquer un
échauffement et un risque d’incendie.
Pour votre propre protection lire et observer toutes les instructions
et les précautions de sûreté specifiques qui parraissent dans ce
manuel aussi bien que les précautions de sûreté générales suiv-
antes:
8. S’assurer que la masse est connectée le plus prés possible
de la zone de travail qu’il est pratique de la faire. Si on place
la masse sur la charpente de la construction ou d’autres
endroits éloignés de la zone de travail, on augmente le
risque de voir passer le courant de soudage par les chaines
de levage, câbles de grue, ou atres circuits. Cela peut
provoquer des risques d’incendie ou d’echauffement des
chaines et des câbles jusqu’à ce qu’ils se rompent.
Sûreté Pour Soudage A L’Arc
1. Protegez-vous contre la secousse électrique:
a. Les circuits à l’électrode et à la piéce sont sous tension
quand la machine à souder est en marche. Eviter tou-
jours tout contact entre les parties sous tension et la
peau nue ou les vétements mouillés. Porter des gants
secs et sans trous pour isoler les mains.
9. Assurer une ventilation suffisante dans la zone de soudage.
Ceci est particuliérement important pour le soudage de tôles
galvanisées plombées, ou cadmiées ou tout autre métal qui
produit des fumées toxiques.
b. Faire trés attention de bien s’isoler de la masse quand
on soude dans des endroits humides, ou sur un planch-
er metallique ou des grilles metalliques, principalement
dans les positions assis ou couché pour lesquelles une
grande partie du corps peut être en contact avec la
masse.
10. Ne pas souder en présence de vapeurs de chlore provenant
d’opéerations de dégraissage, nettoyage ou pistolage. La
chaleur ou les rayons de l’arc peuvent réagir avec les
vapeurs du solvant pour produire du phosgéne (gas forte-
ment roxique) ou autres produits irritants.
c. Maintenir le porte-électrode, la pince de masse, le câble
de soudage et la machine à souder en bon et sûr état
defonctionnement.
PRÉCAUTIONS DE SÛRETÉ POUR LES
MACHINES À SOUDER À TRANSFOR-
MATEUR ET À REDRESSEUR
1. Relier à la terre le chassis du poste conformement au code
de l’électricité et aux recommendations du fabricant. Le dis-
positif de montage ou la piece à souder doit être branché à
une bonne mise à la terre.
d. Ne jamais plonger le porte-électrode dans l’eau pour le
refroidir.
e. Ne jamais toucher simultanément les parties sous ten-
sion des porte-électrodes connectés à deux machines à
souder parce que la tension entre les deux pinces peut
être le total de la tension à vide des deux machines.
2. Dans le cas de travail au dessus du niveau du sol, se protéger
contre les chutes dans le cas ou on recoit un choc. Ne jamais
enroule le câble-électrode autour de n’importe quelle partie
du corps.
2. Autant que possible, l’installation et l’entretien du poste
seront effectués par un électricien qualifié.
3. Avant de faires des travaux à l’interieur de poste, la
debrancher à l’interrupteur à la boite de fusibles.
3. Un coup d’arc peut être plus sévère qu’un coup de soliel,
donc:
4. Garder tous les couvercles et dispostifis de sûreté à leur
place.
a. Utiliser un bon masque avec un verre filtrant approprié
ainsi qu’un verre blanc afin de se protéger les yeux du
rayonnement de l’arc et des projections quand on soude
ou quand on regarde l’arc.
b. Porter des vêtements convenables afin de protéger la
peau de soudeur et des aides contre le rayonnementde
l’arc.
c. Protéger l’autre personnel travaillant à proximité au
soudage à l’aide d’écrans appropriés et non-inflamma-
bles.
4. Des gouttes de laiter en fusion sont émises de l’arc de
soudage. Se protéger avec es vêtements de protection libres
de l’huile, tels que les gants en cuir, chemise épaisse, pan-
talons sans revers, et chaussures montantes.
5. Toujours porter des lunettes de sécurité dans la zone de
soudage. Utiliser des lunettes avec écrans lateraux dans les
zones où l’on pique le laitier.
6. Eloigner les matériaux inflammables ou les recouvrir afin de
prévenir ttout risque d’incendie dû étincelles.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
v
v
MASTER TABLE OF CONTENTS FOR ALL SECTIONS
RETURN TO MAIN INDEX
Page
Safety.................................................................................................................................................i-iv
Installation.............................................................................................................................Section A
Technical Specifications .............................................................................................................A-2
Safety Precautions......................................................................................................................A-4
Select Suitable Location (Stacking, Tilting, Lifting) ....................................................................A-4
Electrical Input Connections.......................................................................................................A-4
Reconnect Procedure.................................................................................................................A-5
Output Connections....................................................................................................................A-6
Operation...............................................................................................................................Section B
Safety Precautions......................................................................................................................B-2
General Description....................................................................................................................B-3
Controls and Settings.................................................................................................................B-4
Case Back Connections.............................................................................................................B-6
Auxiliary Power...........................................................................................................................B-6
Machine Protection.....................................................................................................................B-6
Welding Performance .................................................................................................................B-8
Accessories...........................................................................................................................Section C
Maintenance .........................................................................................................................Section D
Safety Precautions......................................................................................................................D-2
General Maintenance..................................................................................................................D-2
General Component Locations...................................................................................................D-3
Theory of Operation .............................................................................................................Section E
Troubleshooting and Repair.................................................................................................Section F
How to Use Troubleshooting Guide............................................................................................F-2
PC Board Troubleshooting Procedures ......................................................................................F-3
Troubleshooting Guide................................................................................................................F-4
Test Procedures ........................................................................................................................F-13
Oscilloscope Waveforms ..........................................................................................................F-43
Replacement Procedures..........................................................................................................F-49
Retest After Repair....................................................................................................................F-57
Electrical Diagrams............................................................................................................. Section G
Parts Manual............................................................................................................................... P-317
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
Section A-1
Section A-1
TABLE OF CONTENTS
- INSTALLATION SECTION -
Installation.............................................................................................................................Section E
Technical Specifications - Idealarc DC-655 ...............................................................................A-2
Graphic Symbols that Appear on Rating Plate ..........................................................................A-3
Safety Precautions......................................................................................................................A-4
Select Suitable Location.............................................................................................................A-4
Stacking................................................................................................................................A-4
Tilting....................................................................................................................................A-4
Electrical Input Connections.......................................................................................................A-4
Fuse and Wire Sizes.............................................................................................................A-4
Ground Connection..............................................................................................................A-4
Input Power Supply Connections ........................................................................................A-5
Reconnect Procedure.................................................................................................................A-5
Output Connections ...................................................................................................................A-6
Electrode and Work Cables..................................................................................................A-6
Auxiliary Power and Control Connections ...........................................................................A-7
Auxiliary Power Table.....................................................................................................A-7
115VAC Duplex Receptacle...........................................................................................A-7
230V Receptacle............................................................................................................A-7
14 Pin MS Type Receptacle...........................................................................................A-7
Terminal Strips ...............................................................................................................A-8
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
A-2
A-2
INSTALLATION
TECHNICAL SPECIFICATIONS – DC-655
INPUT - THREE PHASE ONLY
Input Current at Rated Output
100% Duty Cycle 60% Duty Cycle
Standard
Voltage
Code
Number
122/61
150/75
230/460/60
230/460/575/60
208/416/60
460/60
10501
10502
10503
10504
10505
10506
10507
10508
10509
10510
122/61/49
135/67.5
61
150/75/60
166/83
75
49
60
575/60
122/70
74/56
64
140/70
68
150/86
90/69
78
172/86
83
230/400/50/60*
380/500/50/60*
440/50/60
200/400/50/60
415/50/60
RATED OUTPUT
Duty Cycle
100% Duty Cycle
NEMA Class I (100)*
60% Duty Cycle
Amps
650
Volts at Rated Amperes
44
815
44
OUTPUT
Voltage Range
Current Range
Maximum Open Circuit Voltage
46 CV Mode
Auxiliary Power
See the OPERATION section for
Auxiliary Power
13-44 DC
50-815
68 CC Mode
information by model
RECOMMENDED INPUT WIRE AND FUSE SIZES
TYPE 80°C
COPPER WIRE GROUND WIRE
Copper
INPUT
VOLTAGE /
FREQUENCY
HERTZ
INPUT AMPERE
RATING ON
NAMEPLATE
(SUPER LAG)
OR BREAKER
SIZE (AMPS)1
IN CONDUIT
IN CONDUIT
AWG(IEC-MM2) SIZES AWG(IEC-MM2) SIZES
40°C (104°F) Ambient
208
230
416
460
575
200
230
380
400
415
440
500
60
60
60
60
60
50/60
50/60
50/60
50/60
50/60
50/60
50/60
135
122
67.5
61
1 (43)
1 (43)
6 (14)
6 (14)
8 (8.4)
1/0 (54)
1 (43)
4 (21)
4 (21)
6 (14)
6 (14)
6 (14)
4 (21)
4 (21)
6 (14)
6 (14)
8 (8.4)
4 (21)
4 (21)
6 (14)
6 (14)
6 (14)
6 (14)
6 (14)
250 Amp
225 Amp
125 Amp
110 Amp
90 Amp
250 Amp
225 Amp
125 Amp
125 Amp
110 Amp
110 Amp
110 Amp
49
140
122
74
70
68
64
56
PHYSICAL DIMENSIONS
HEIGHT
27.5 in
699 mm
WIDTH
22.2 in
564 mm
DEPTH
38.0 in
965 mm
WEIGHT
720 lbs.
326 kg.
* European models meet IEC974-1 standards.
1
Also called “inverse time” or “thermal/magnetic” circuit breakers; circuit breakers which have a delay in tripping action that decreases as the magnitude of the current increases.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
A-3
A-3
INSTALLATION
GRAPHIC SYMBOLS THAT APPEAR ON
RATING PLATE (LOCATED ON CASE BACK)
Constant Voltage Output
3 Phase transformer with
rectified DC output
Characteristics
INPUT POWER
THREE PHASE
GMAW
FCAW
Designates welder complies with
National Electrical Manufacturers
Association requirements EW 1
Class I with 100% duty cycle at
650Amps output. (Domestic,
Canadian, and Export models)
Designates welder can be used
in environments with increased
hazard of electric shock.
(European models)
S
NEMA EW 1 (100%)
Designates welder complies with
low voltage directive and with
EMC directive. (European
models)
CE
Designates welder complies with
International
Electrotechnical
IEC 974-1
Commission requirements 974-1.
(European Models)
Designates welder complies with
both Underwriters Laboratories
(UL) standards and Canadian
Standards Association (CSA)
standards. (Canadian Model)
R
Designates the degree of envi-
ronmental protection provided by
the power sources enclosure.
NRTL/C
IP-23
Designates welder complies with
Underwriters Laboratories (UL)
standards. (Domestic Models)
R
Constant Current Output
Characteristics
NRTL
SMAW
SAW
U
o
Open Circuit Output Voltage
Input Voltage Rating(s)
Input Current Rating(s)
U
1
I
1
X
Output Duty Cycle Rating(s)
Output Voltage Rating(s)
U
2
I
Output Current Rating(s)
2
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
A-4
A-4
INSTALLATION
Read this entire installation section
before you start installation.
INPUT
CONTACTOR (CR1)
INPUT POWER SUPPLY
CABLE WITH BUSHING
OR BOX CONNECTOR
SAFETY PRECAUTIONS
WARNING
RECONNECT
PANEL ASSEMBLY
ELECTRIC SHOCK can kill.
• Only qualified personnel should
perform this installation.
•
Turn the input power OFF at the
disconnect switch or fuse box
before working on this equipment.
• Turn the Power Switch on the DC-655 “OFF” before
connecting or disconnecting output cables, wire
feeder or remote connections, or other equipment.
FIGURE A.1 - ELECTRICAL INPUT CONNECTIONS
• Do not touch electrically hot parts.
Use input wire sizes that meet local electrical codes or
see the Technical Specifications page in this manual.
• Always connect the Idealarc DC-655 grounding ter-
minal (located on the welder near the reconnect
panel) to a good electrical earth ground.
Input power supply entry is through the hole in the
Case Back Assembly. See Figure A.1 for the location
of the machine’s input cable entry opening, Input
Contactor (CR1), and reconnect panel.
SELECT SUITABLE LOCATION
FUSE AND WIRE SIZES
Place the welder where clean cooling air can freely cir-
culate in through the front louvers and out through the
rear louvers. Dirt, dust or any foreign material that can
be drawn into the welder should be kept at a mini-
mum. Failure to observe these precautions can result
in excessive operating temperatures and nuisance
shut-downs.
Protect the input circuit with the super lag fuses or
delay type circuit breakers listed on the Technical
Specifications page of this manual for the machine
being used. They are also called inverse time or ther-
mal/magnetic circuit breakers.
DO NOT use fuses or circuit breakers with a lower amp
rating than recommended. This can result in “nui-
sance” tripping caused by inrush current even when
machine is not being used for welding at high output
currents.
STACKING
The DC-655 may be stacked three-high provided the
bottom machine is on a stable, hard, level surface. Be
sure that the two pins in the roof fit into the slots in the
base of the DC-655 above it.
GROUND CONNECTION
Ground the frame of the machine.
terminal marked with the symbol is located inside
A ground
TILTING
Do not place the machine on a surface that is inclined
enough to create a risk of the machine falling over.
the case back of the machine near the input contactor.
Access to the input box assembly is at the upper rear
of the machine. See your local and national electrical
codes for proper grounding methods. Use grounding
wire sizes that meet local electrical codes or see the
Technical Specifications page in this manual.
ELECTRICAL
INPUT CONNECTIONS
Before installing the machine check that the input sup-
ply voltage, phase, and frequency are the same as the
voltage, phase, and frequency as specified on the
welder nameplate.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
A-5
A-5
INSTALLATION
INPUT POWER SUPPLY CONNECTIONS
RECONNECT PROCEDURE
A qualified electrician should connect the input power
supply leads.
WARNING
Electric Shock Can Kill
1. Follow all national and local electrical codes.
2. Use a three-phase line.
• Disconnect input power before per-
forming this procedure.
3. Remove the input access door at upper rear of the
machine.
4. Follow input supply connection diagram located
on the inside of the door.
Multiple voltage machines are shipped connected to
the highest input voltage listed on the machine’s rating
plate. Before installing the machine, check that the
reconnect panel in the input box assembly is connect-
ed for the proper voltage.
5. Connect the three-phase AC power supply leads
L1, L2, and L3 to the input contactor
terminals in the input box assembly. See Figure
A.1.
CAUTION
Failure to follow these instructions can cause immedi-
ate failure of components within the machine.
To reconnect a multiple voltage machine to a different
voltage, remove input power and follow the input con-
nection diagram located on the inside of case back
input access door.
1. For dual voltage sample machine reconnect
instructions, see Figure A.2.
DUAL VOLTAGE MACHINE
Do not operate with covers
removed
Do not touch electrically live parts
INPUT SUPPLY CONNECTION DIAGRAM
IMPORTANT: CHANGE LINK POSITIONS AND CONTROL TRANSFORMER CONNECTIONS.
NOTE: MACHINES ARE SHIPPED FROM FACTORY CONNECTED FOR OVER 300 VOLTS
Disconnect input power before
Only qualified persons should install,
use or service this equipment
servicing
CONNECTION FOR HIGHEST RATING PLATE VOLTAGE
1. TURN OFF THE INPUT POWER USING THE DISCONNECT SWITCH AT THE FUSE BOX.
2. DISCONNECT AND INSULATE THE H2 LEAD TERMINAL WITH TAPE TO PROVIDE AT
LEAST 600 VOLT INSULATION.
CR1
W
L3
3. CONNECT L1, L2
&
L3 INPUT SUPPLY LINES AND H1
&
H3 CONTROL TRANSFORMER
INPUT
LINES
V
L2
LEADS TO THE INPUT SIDE OF CR1 CONTACTOR AS SHOWN.
CONTACTOR
U
4. CONNECT TERMINAL MARKED
CODES.
TO GROUND PER LOCAL AND NATIONAL ELECTRIC
L1
H1
GND
5. MOUNT THE LINKS IN THE POSITIONS SHOWN; DOUBLE OR TRIPLE STACK THE LINKS
IN THREE POSITIONS. LOOP THE FLEX LEAD IN THE POSITION SHOWN; POSITIONING
THE LUGS TO MAINTAIN MAXIMUM CLEARANCE TO THE LINKS. INSTALL AND TIGHTEN
ALL OF THE HEX NUTS.
H2
H3
CONTROL
TRANSF.
LINKS
CONNECTION FOR LOWEST RATING PLATE VOLTAGE
1. TURN OFF THE INPUT POWER USING THE DISCONNECT SWITCH AT THE FUSE BOX.
2. DISCONNECT AND INSULATE THE H3 LEAD TERMINAL WITH TAPE TO PROVIDE AT
LEAST 600 VOLT INSULATION.
CR1
W
V
L3
L2
L1
INPUT
LINES
3. CONNECT L1, L2
&
L3 INPUT SUPPLY LINES AND H1
&
H2 CONTROL TRANSFORMER
LEADS TO THE INPUT SIDE OF CR1 CONTACTOR AS SHOWN.
CONTACTOR
U
4. CONNECT TERMINAL MARKED
CODES.
TO GROUND PER LOCAL AND NATIONAL ELECTRIC
H1
GND
5. MOUNT THE LINKS IN THE POSITIONS SHOWN. CONNECT THE FLEX LEAD AS SHOWN;
POSITIONING THE LUGS TO MAINTAIN MAXIMUM CLEARANCE TO THE LINKS.
INSTALL AND TIGHTEN ALL OF THE HEX NUTS.
H3
H2
CONTROL
TRANSF.
D-UF
LINKS
THE LINCOLN ELECTRIC CO., CLEVELAND OHIO U.S.A.
M18225
FIGURE A.2 - DUAL VOLTAGE MACHINE RECONNECTION PROCEDURE
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
A-6
A-6
INSTALLATION
2. Connect the electrode cable to the positive terminal
marked “+”.
OUTPUT CONNECTIONS
ELECTRODE AND WORK CABLES
Use the shortest possible cable lengths. See Table A.1
for recommended cable sizes based on length.
3. Remove the terminal strip access cover panel on
the lower case front. Refer to Figure A.3 for the
location.
4. Work Sense lead #21 from the 14 Pin MS-recepta-
cle must be connected to “-21”on the terminal strip.
Note: This is how the DC-655 is shipped from the
factory.
TABLE A.1
Cable Sizes for Combined Lengths of Copper
Electrode and Work Cable
Cable Length
ft. (m)
Parallel Cables
Cable Size
5. Replace the terminal strip access cover panel.
0 (0)
to 100 (30.4)
2
2
2
2/0 ( 70mm2)
3/0 ( 95mm2)
4/0 (120mm2)
100 (30.4) to 200 (60.8)
200 (60.8) to 250 (76.2)
For Negative Polarity:
The output terminals are located at the lower front of
the welder behind a hinged door. Refer to Figure A.3.
Route the welding cables through the slotted strain
reliefs of the base to the welding terminals.
1. Connect the electrode cable to the appropriate high
inductance (-) terminal (marked "
or to the low inductance (-) terminal (marked
") if using NR203Ni 1% electrode.
")
"
LOW INDUCTANCE TERMINAL
2. Connect the work cable to the positive terminal
marked “+”.
On the DC-655, the inside right Negative (-) output ter-
minal is lower choke inductance. This terminal is
presently only recommended for CV mode welding
with NR203Ni 1% negative polarity procedures.. All
other processes are to be welded using the outside
right Negative (-) output terminal with higher choke
inductance. CC mode processes must use high
inductance.
3. Remove the terminal strip access cover panel on the
lower case front. Refer to Figure A.3 for the location.
4. Work Sense lead #21 from the 14 Pin MS-recepta-
cle must be connected to “+21”on the terminal
strip.
5. Replace the terminal strip access cover panel.
For Positive Polarity:
1. Connect the work cable to the high inductance (-)
terminal (marked "
").
14 PIN MS RECEPTACLE
POSITIVE
OUTPUT
TERMINAL
LOW INDUCTANCE
HIGH INDUCTANCE
NEGATIVE OUTPUT
NEGATIVE OUTPUT
TERMINAL
TERMINAL
TERMINAL STRIP
COVER PANEL
FIGURE A.3 - OUTPUT CONNECTIONS
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
A-7
A-7
INSTALLATION
14-PIN MS TYPE RECEPTACLE
AUXILIARY POWER AND
CONTROL CONNECTIONS
(For MS3106A-20-27PX Plug. L.E.C. Part #S12020-32)
Located at the lower front of the welder behind a
hinged door is a 115 VAC duplex receptacle for auxil-
iary power (Domestic and Canadian Models only) and
a 14-pin MS type receptacle for connection of auxiliary
equipment such as wire feeders. Also, terminal strips
with 115 VAC and connections for auxiliary equipment
are located behind the access panel on the lower case
of the welder. A 220 VAC receptacle for a water cooler
(European and Export Models only) is located on the
case back.
Refer to the Figure A.4 for the available circuits in the
14-pin receptacle.
42 VAC is available at receptacle pins I and K. A 10
amp circuit breaker protects this circuit.
115 VAC is available at receptacle pins A and J
(Domestic, Canadian and Export Models). This circuit
is protected by a circuit breaker (see Auxiliary Power
Table). Note that the 42 VAC and 115 VAC circuits are
electrically isolated from each other. However, on the
European model one line of the 115 VAC is connected
to chassis ground.
AUXILIARY POWER TABLE
Voltage and Circuit Breaker Ratings at Auxiliary Power
Connections for Various Models
FIGURE A.4 - FRONT VIEW OF 14-PIN
CONNECTOR RECEPTACLE
Auxiliary
Power
Connections
Domestic
Models
(60Hz)
Canadian
Model
European
Models
Export
Models
(230/460/575V/60 Hz) (50/60 Hz) (50/60 Hz)
K=42
At Duplex
Receptacle
115V 20A
115V 20A
115V 20A
42V 10A
115V 15A
115V 15A
115V 15A
42V 10A
No Duplex No Duplex
J=31
I=41
A=32
B=GND
Terminal strip
terminals 31 & 32
115V 15A
115V 15A
L
N
MS-Receptacle
pins A & J
Open Circuit 115V 15A
C=2
D=4
E=77
H=21
MS-Receptacle
pins I & K
42V 10A
220V 2A
42V 10A
220V 2A
G=75
F=76
At 220V
Receptacle
No Receptacle
No Receptacle
M
PIN
LEAD NO.
FUNCTION
A
B
C
D
E
F
32
GND
2
115 VAC
115 VAC DUPLEX RECEPTACLE (DOMESTIC AND
CANADIAN MODELS ONLY)
Chassis Connection
Trigger Circuit
Trigger Circuit
Output Control
Output Control
Output Control
The 115 VAC duplex receptacle is protected by a cir-
cuit breaker located below the receptacle (see
Auxiliary Power Table). Receptacle is a NEMA 5-20R
(protected by a 20 amp breaker) on Domestic Models
and a NEMA 5-15R (protected by a 15 amp breaker) on
Canadian Models.
4
77
76
75
G
H
I
21
41
Work Sense Connection2
42 VAC
J
K
L
M
N
31
42
---
---
---
115 VAC1.
42 VAC
---
---
---
230 VAC RECEPTACLE (EUROPEAN AND EXPORT
MODELS ONLY)
A Continental European receptacle is located on the
rear panel for supplying 220 VAC to a water cooler. The
receptacle has a protective cover to prevent acciden-
tal contact and is a Schuko type. The circuit is pro-
tected by a 2 amp circuit breaker also located on the
rear panel. This circuit is electrically isolated from all
other circuits, but on the European Models one line is
connected to chassis ground.
1.
2.
115VAC circuit is not present in the 14-pin connector on IEC 974-
1 European models.
As shipped from the factory Lead #21 from the 14-pin connector is
connected to “-21” on the terminal strip. This is the configuration for
positive welding. If welding negative polarity, connect lead #21 to
the “+21” connection point on the terminal strip.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
A-8
A-8
INSTALLATION
TERMINAL STRIPS
Terminal strips are available behind the cover panel on
the lower case front to connect wire feeder control
cables that do not have a 14-Pin MS-type connector.
Refer to Figure A.3 for the location of this cover panel.
These terminals supply the connections as shown in
the following Terminal Strip charts. See Auxiliary
Power Table for rating of circuit breaker in 115 VAC cir-
cuit. Remove a plug button from the terminal strip
cover and install an appropriate strain relief clamp for
the cable being used. NOTE: There are two work
sense lead connection points on the terminal strip.
Connect both the work sense lead #21 from the 14-pin
connector and #21 lead of the control cable to “-21”
when welding positive polarity or to “+21” when weld-
ing negative polarity.
TERMINAL STRIP 1 (T.S.1)
Lead No.
Function
75
76
77
Output Control
Output Control
Output Control
TERMINAL STRIP 2 (T.S.2)
Lead No.
Function
+21
-21
41
4
2 (42 VAC)
31
32
Work Connection
Work Connection2
42 VAC
Trigger Circuit
Trigger Circuit (42 VAC)
115 VAC1
115 VAC1
1
115 VAC circuit is also present on IEC 974-1 European models.
2 If connecting a feeder cable directly to the terminal strip, Lead #21
from the cable is connected to “-21” on the terminal strip for positive
welding. If welding negative polarity, connect lead #21 to the “+21”
connection point on the terminal strip.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
Section B-1
Section B-1
TABLE OF CONTENTS
- OPERATION SECTION -
Operation...............................................................................................................................Section B
Safety Precautions......................................................................................................................B-2
General Description....................................................................................................................B-3
Recommended Processes and Equipment .........................................................................B-3
Design Features and Advantages........................................................................................B-3
Welding Capability................................................................................................................B-3
Controls and Settings.................................................................................................................B-4
Case Back Connections.............................................................................................................B-6
220 VAC Auxiliary Receptacle..............................................................................................B-6
220 VAC 2 Amp Circuit Breaker...........................................................................................B-6
Auxiliary Power ...........................................................................................................................B-6
Machine Protection.....................................................................................................................B-6
Thermal Fan Control.............................................................................................................B-6
Fan Motor Fuse....................................................................................................................B-6
Machine Shutdown ..............................................................................................................B-6
Thermal Shutdown...............................................................................................................B-7
Over Current Protection Shutdown......................................................................................B-7
Remote Control Leads Fault Protection Shutdown.............................................................B-7
Shorted Rectifier Fault Protection........................................................................................B-7
Idle Shutdown Timer ............................................................................................................B-7
Welding Performance .................................................................................................................B-8
Low Inductance Terminal .....................................................................................................B-8
CV Mode Current Limiting....................................................................................................B-8
CC Mode Arc Force .............................................................................................................B-8
CC Mode Hot Start ..............................................................................................................B-8
CC Mode Arc Gouging.........................................................................................................B-8
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
B-2
B-2
OPERATION
OPERATING INSTRUCTIONS
Read and understand this entire section of operating
instructions before operating the machine.
SAFETY PRECAUTIONS
WARNING
ELECTRIC SHOCK can kill.
• Do not touch electrically live parts or
electrodes with your skin or wet cloth-
ing.
• Insulate yourself from the work and ground.
• Always wear dry, insulating gloves.
FUMES AND GASES can be
dangerous.
• Keep your head out of fumes.
• Use ventilation or exhaust to remove fumes from
breathing zone.
CUTTING SPARKS can cause
fire or explosion.
• Keep flammable material away.
• Do not cut containers that have held combustibles.
ARC RAYS
can burn.
• Wear eye, ear, and body protection.
Observe additional Safety Guidelines detailed in
the beginning of this manual.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
B-3
B-3
OPERATION
• Power on/off switch with pilot light and thermostat
tripped indicator light.
GENERAL DESCRIPTION
The DC-655 is an energy efficient constant voltage DC
power source that produces outstanding arc charac-
teristics for multiple CV or CC welding processes.
• Full range output voltage (CV mode) and current (CC
mode) control for easy operation.
• Panel switches behind a latched front panel for
remote or local output control, output on or remote
selection, and CC, CV Sub-arc or CV MIG mode
selection.
Four models are available:
Domestic - all 60 Hertz models except
230/460/575v.
NEMA Class 1 rated
• Panel knob settable CC arc force control with built-
in adjustable “Hot Start”.
Canadian - 230/460/575v 60 Hertz
NEMA Class 1 rated
• High efficiency output, and selectable “sleep mode”
idle mode timer which shuts down input power if not
used for extra energy conservation.
European - 50/60 Hertz models “CE” qualified
and rated for IEC 974-1
Export - 50/60 Hertz models NEMA Class 1 rated
• Fan as needed (F.A.N.). Solid state thermally con-
trolled fan operates cooling fan only when required.
Minimizes power consumption, operating noise and
dust intake.
RECOMMENDED PROCESSES AND
EQUIPMENT
The DC-655 is designed for CV or CC processes.
• Hinged cover to protect output terminals and auxil-
iary connections.
• Electronic and thermostatic protection for current
overload and excessive temperatures.
CV processes include: GMAW (MIG) and FCAW (flux-
cored) welding, plus the capability of CV submerged
arc welding and air carbon arc gouging. It produces
outstanding welding performance with a single range
full output control knob.
• 42 VAC, 10 amp auxiliary power available for the wire
feeder; circuit breaker protected.
• 115 VAC, auxiliary power available for the wire feed-
er; circuit breaker protected. 20 amp breaker on
Domestic model and 15 amp breaker on Canadian,
European, and Export Models.
CC processes include stick welding, CC submerged
arc and superior air carbon arc gouging with up to 3/8”
(10 mm) diameter carbons. The same single range full
output control knob is used and paralleling capability
is provided.
• 115 VAC duplex plug receptacle available on
Domestic and Canadian Models. 20 amp breaker on
Domestic Models and 15 amp breaker on Canadian
Model.
The DC-655 is recommended for use with Lincoln’s
DH-10 or LN-10 as well as the LN-7*, LN-7 GMA*, LN-
742, LN-8*, LN-9*, LN-9 GMA*, LN-23P and LN-25
semiautomatic wire feeders. It is also recommended
for use with the NA-3, NA-5 and NA-5R automatic
feeders. “Cold starting” for sub-arc or across arc
“touch-sensing” can be used.
• 220 VAC receptacle on European and Export models
for connecting to a water cooler. Protected by 2 amp
breaker.
• Single MS-type (14-pin) connection for wire feeder.
* The 14-pin MS receptacle on the European models
does not provide 115 VAC for these feeders; 115
VAC must be obtained from terminal strip.
• Optional Field Installed Digital or Analog Voltmeter/
Ammeter kits are available.
• Optional dual feeder kit for like polarity connection of
two wire feeders. Easy panel installation.
Two DC-655’s may be paralleled in a “master” and
“slave” interconnection using the K1611-1 Paralleling
kit.
• Optional Dual Process Switch for two processes
with polarity change and electrical isolation.
DESIGN FEATURES AND
ADVANTAGES
• Separate output terminals for selecting high or low
inductance as recommended for the welding
process.
WELDING CAPABILITY
The DC-655 has the following Output and Duty Cycle
based on operation for a 10 minute period:
650 Amps, 44 Volts at 100%
815 Amps, 44 Volts at 60%
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
B-4
B-4
OPERATION
CONTROLS AND SETTINGS
All operator controls and adjustments are located on the case front of the DC-655. Refer to Figures B.1, and B.2
and corresponding explanations.
8
9
2
3
1
DC-655
7
6
5
4
FIGURE B.1 CONTROL PANEL CONTROLS
1. INPUT
gle switch turns the machine on or off. Putting the
switch in the ON position energizes the
POWER ON/OFF SWITCH - This tog-
remote device such as a wire feeder closes the #2 and
#4 circuit in the MS-receptacle or terminal strip. When
this switch is in the ON position the machine’s output
terminals will be electrically energized all the time.
machine’s input contactor applying input power to
the machine. Switching the switch to the OFF
position de-energizes the input contactor. This
switch is also used to reset a machine shutdown.
(See Machine Shutdown section)
5. LOCAL/REMOTE CONTROL SWITCH - When
this switch is set to the LOCAL
position, con-
trol of the output voltage is via the output control
on the DC-655’s control panel. When this switch is
2. PILOT LIGHT - When the power switch is in the
ON position the machine’s white pilot light will illu-
minate. If the input contactor de-energizes the
machine in a shutdown situation, the pilot will still
illuminate. In this situation it will be necessary to
reset the machine by switching the power switch to
the OFF then ON position. (See Machine
Shutdown section)
set to the remote
position, control is through a
remote source such as a wire feeder via the #75,
#76, and #77 leads in the MS-receptacle or termi-
nal strip.
6. CC STICK/CV SUBARC/CV MIG MODE SWITCH -
This switch selects the proper welding characteris-
tics for the process being used:
CC Stick provides a constant current output
characteristic through the 50 to 815 amp
range. The current is adjusted within this
range by the Output Control dial. The open
circuit (no load) voltage will be about 68 volts
in this mode.
3. OUTPUT
CONTROL - This control provides
continuous control of the machine’s output from
minimum to maximum as it is rotated clockwise.
The CV mode voltage range of control is 13 to 44V.
The CC mode current range of control is 50 to
815A.
This mode is used for stick welding (SMAW)
and CC air carbon-arc gouging, and employs
a “Hot Start” feature and an Arc Force Control.
4. OUTPUT TERMINALS ON/REMOTE - When this
switch is in the REMOTE
position, the DC-655’s
output terminals will be electrically “cold” until a
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
B-5
B-5
OPERATION
CC mode may also be used for CC submerged arc
with appropriate arc-sensing CC(VV) wire feeders
if arc force is set high enough. Refer to Welding
Performance section.
7. ARC FORCE CONTROL - This control is only func-
tional in CC Stick mode. It prevents “stubbing” of
the electrode by providing the extra weld current
that linearly increases as the welding voltage
decreases below a level determined by the setting
of the constant current control.
CV MIG provides a constant voltage output char-
acteristic through the 13 to 44 volt range. The volt-
age is adjusted within this range by the Output
Control dial.
The Arc Force control knob, located behind the
latched cover, adjusts arc force from “Min” (no cur-
rent increase) to “Max” (higher short circuit current).
The “mid” position (#5) is recommended for most
CC welding. Refer to the Welding Performance
Section.
The dynamic characteristics of this mode are ideal
for open arc processes including, MIG/MAG
(GMAW), Innershield®, and other cored wire
(FCAW) processes. Faster travel submerged arc
processes and CV air carbon-arc gouging may
also use this mode. Refer to the Welding
Performance section.
8. OPTIONAL VOLTMETER & AMMETER - Digital or
analog meter kits are available as field installed
options. Refer to the Accessories Section of this
manual.
CV Sub-Arc provides the same constant voltage
output control range as CV MIG, but the dynamic
characteristics of this mode make possible
improved CV (constant wire speed) submerged arc
welding. This improved process is most notice-
able on high deposition slow travel speed welds.
Fast travel, narrow bead subarc welds will have
better performance in CV MIG mode.
9. THERMAL PROTECTION LIGHT
- If the
machine overheats due to lack of proper air flow
through the machine or due to exceeding the
machine’s duty cycle, thermostats will disable the
welding output and this light will illuminate. Input
power is still applied to the machine and the cool-
ing fan will continue to run. When the machine
cools the welding output will resume.
FIGURE B.2 LOWER CASE FRONT CONTROLS & CONNECTIONS
1
2
3
4
5
7
6
1. 115 VAC DUPLEX RECEPTACLE (Domestic and
Canadian Models) This receptacle provides up to
20 amps of 115 VAC auxiliary power on the
2. 115 VAC CIRCUIT BREAKER
- This breaker
protects the 115 VAC auxiliary circuits located in
the duplex receptacle, terminal strip and MS-
receptacle. Breaker is rated 20 amps on Domestic
Models and 15 amps on all other models.
Domestic Models
Canadian Model.
and up to 15 amps on the
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
B-6
B-6
OPERATION
3. 42 VAC 10 AMP CIRCUIT BREAKER
- This
DC-655 machines can also supply 115 volt AC auxil-
iary power through the wire feeder receptacle. A 20
amp circuit breaker on the Domestic model, and a 15
amp on the Canadian and Export models protects the
115 volt circuit from overloads. 115 VAC is not avail-
able in the MS-receptacle on the European models.
breaker protects the 42 VAC auxiliary circuits locat-
ed in the terminal strip and MS-receptacle.
4. 14-PIN MS-RECEPTACLE - This connector pro-
vides easy connection for a wire feeder control
cable. It provides connections for auxiliary power,
output switching, remote output control, wire feed-
er voltmeter sense lead and ground. Refer to 14-
Pin MS Type Receptacle in the Installation
Section of this manual for information about the cir-
cuits made available at this receptacle.
CAUTION
Note that some types of equipment, especially pumps
and large motors, have starting currents which are sig-
nificantly higher than their running current. These high-
er starting currents may cause the circuit breaker to
open. If this situation occurs, the user should refrain
from using the DC-655 auxiliary power for that equip-
ment.
5. TERMINAL STRIP COVER PANEL - Remove this
panel to gain access to the circuits made available
at the terminal strip and the 4-pin receptacle for the
optional paralleling kit. This terminal strip contains
the same circuits as the 14-pin MS-receptacle.
The cover also provides for installation of cable
strain relief clamps.
MACHINE PROTECTION
6. POSITIVE OUTPUT TERMINAL - This output ter-
minal is for connecting a welding cable. To change
welding polarity and for proper welding cable size
refer to Electrode and Work Cables in the
Installation Section of this manual.
THERMAL FAN CONTROL
The machine’s cooling fan remains off when the tem-
perature of the rectifiers and windings inside the
machine are below that requiring air flow cooling, as
determined by electronic monitoring of several thermal
sensors and the welding current of the machine.
Depending upon the operating temperature of the
machine, the fan may remain off while welding but
once the fan is activated, it will remain on for at least 5
minutes to assure proper cooling. This feature saves
energy and also minimizes the amount of dirt and
other air borne particles being drawn into the machine.
7. NEGATIVE OUTPUT TERMINALS - These output
terminals are for connecting a welding cable to
either the High Inductance or Low Inductance
Terminal for desired arc characteristics. To change
welding polarity and for proper welding cable size
refer to Electrode and Work Cables in the
Installation Section of this manual.
CASE BACK CONNECTIONS
FAN MOTOR FUSE
(European Model)
220 VAC AUXILIARY RECEPTACLE
(European and Export Models)
A 10 amp slow blow fuse protects the fan motor cir-
cuit. This fuse is located inside the DC-655 mounted
on the fan motor bracket.
This receptacle provides up to 2 amps of 220 VAC
auxiliary power for a water cooler.
220 VAC 2 AMP CIRCUIT BREAKER
(European and Export Models)
MACHINE SHUTDOWN
This breaker protects the 220 VAC auxiliary circuit
located in the 220 VAC receptacle.
The DC-655 provides shutdown modes for thermal
over-heating, excessive load currents and faults. It
also provides an idle timer shutdown feature for addi-
tional operating economy.
AUXILIARY POWER
42 volt AC auxiliary power, as required for some wire
feeders, is available through the wire feeder recepta-
cle. A 10 amp circuit breaker protects the 42 volt cir-
cuit from overloads.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
B-7
B-7
OPERATION
THERMAL SHUTDOWN
SHORTED RECTIFIER FAULT PROTECTION
This welder has thermostatic protection from exces-
sive duty cycles, overloads, loss of cooling, and high
ambient temperature. When the welder is subjected to
an overload or loss of cooling, a thermostat will open.
This condition will be indicated by the illumination of
the yellow Thermostatic Protection Light on the case
front (see Figure B.1). The fan will continue to run to
cool the power source. No welding is possible until the
machine is allowed to cool and the Thermostatic
Protection Light goes out.
If a short occurs across one of the silicon controlled
rectifiers of the DC-655, a potentially hazardous AC
voltage could appear across the welding output termi-
nals, even in idle mode when no output should be pre-
sent. If such a fault occurs, the DC-655 will shut down
the input primary voltage to the transformer to prevent
the fault output. Control PC board LED3, input shut-
down light, turns on.
If this input shutdown occurs the input power pilot
light remains lit, since the power switch is ON and
control power is still present. Welding output or auxil-
iary supply output will not be present.
OVER CURRENT PROTECTION
SHUTDOWN
Average Current Shutdown
To protect the SCR’s , the DC-655 will shut down to
essentially no output if the output current averages
over 900 amps for about 5-6 seconds, and in less than
0.3 seconds if averaging over 1200 amps (shorter time
for higher current). Control PC board LED4, shutdown
light, will turn on.
This input shut down is reset by turning the DC-655
input power off, then on. If the fault is not corrected
however, the shutdown will re-occur when turning on
the input power.
IDLE SHUTDOWN TIMER
For additional operating economy, the DC-655 can be
set up to automatically shut off the primary input
power to the main transformer after a selectable time
(1/2 or 2 hr.) has expired without welding. The unex-
pired timer is reset with each weld.
This average current shut down can only be reset by
opening the feeder gun trigger, or switching the DC-
655 Output/Remote switch out of the “on” position.
Peak Current Shutdown
The idle mode timer is activated by setting Switch #1
(left most) of the DIP Switch located on the lower-cen-
ter of the DC-655 Control PC board. from the down
(Off) position to the up (On) position. Setting Switch
#2 of the DIP switch to up (On) sets the shutdown time
to 2 hours. Setting Switch #2 of the DIP switch to
down (Off) sets the shutdown time to 1/2 hour.
Shutdown is reset by turning the DC-655 input power
off, then on.
To protect the SCRs, the DC-655 will shut down imme-
diately to essentially no output if the peak output cur-
rent exceeds 2500 amps (about 1800A average).
Control PC board LED4, shutdown light, will turn on.
This peak current shut down can be reset by turning
the DC-655 input power off, then on.
REMOTE CONTROL LEADS FAULT
PROTECTION SHUTDOWN
1
The remote control leads from the 14-pin receptacle or
terminal strip are protected against high voltage faults
to the electrode circuit or auxiliary voltage supplies. If
such a fault occurs, the DC-655 will shut down the
input primary voltage to the transformer to prevent the
fault output. Control PC board LED3, input shutdown
light, turns on.
Switch #1 Timer On/Off
(UP=ON, Down=OFF)
1
2
3
4
DIP Switch
If this input shutdown occurs the input power pilot
light remains lit, since the power switch is ON and
control power is still present. Welding output or auxil-
iary supply output will not be present.
Switch #2 Time selection
(UP=2 hours, Down=1/2 hour)
This input shut down is reset by turning the DC-655
input power off, then on. If the fault is not corrected
however, the shutdown will re-occur when turning on
the input power.
Note: See Weld Performance section
for use of switch #3 and #4.
1 Note on earlier machines: LED4 will turn on and output will be
disabled if this fault occurs.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
B-8
B-8
OPERATION
As a general guideline for CC welding, set Arc Force to
“Mid” position and increase (typically to no more than
#7) as necessary to prevent “stubbing” or “pop-outs”
while welding. This higher arc force is recommended
especially for low end 6010 stick welding.
WELDING PERFORMANCE
LOW INDUCTANCE TERMINAL
The inside right Negative (-) terminal is lower choke
inductance and presently is only recommended for
welding with NR203Ni 1% procedures. All other
processes are to be welded using the outside right
Negative (-) terminal with higher choke inductance.
VOLTS
OCV
CV MODE CURRENT-LIMITING
Hot Start
CV MIG and CV Sub-Arc modes employ electronic
current limiting to limit excessive short circuit output
current which can result in undesirable arc character-
istics or nuisance over current protection shutdown
(see Machine Protection section).
Max. Arc Force
Min. Arc Force
Low
Setting
Hi
AMPS
As shipped, the DC-655 is set for “Hi” current limiting,
which maintains constant voltage until the welding
current exceeds a level proportional to the voltage set-
ting, then falls off linearly at about 10 volts per 100
amps to a limited short circuit current. “Lo” current
limiting provides the same short circuit current, but the
arc voltage begins to linearly fall off at lower current, at
about 5 volts per 100 amps.
Setting
CC OUTPUT
CC MODE HOT START
Hot start is built-in for CC mode stick and carbon arc
starting. Hot Start provides an extra weld current
“boost” at the arc strike which increases with higher
current settings. This Hot Start level exponentially
decays to the weld current setting in a few seconds.
“Hi” is recommended for all CV processes, especially
for CV subarc and CV arc gouging, but “Lo” tends to
“soften” the arc more when welding NR203Ni 1% on
the Low Inductance (-) terminal. If “Lo” is desired,
switch #4(right-most) of the DIP switch located on the
lower-center of the DC-655 Control PC board needs to
be switched from up (Hi) position to down (Lo) posi-
tion.
Adjustment of the Hot Start shouldn’t be necessary,
but an unsealed trimmer (R81) is provided on the DC-
655 Control PC Board to adjust hot start. Full counter-
clockwise adjustment will reduce Hot Start to zero.
Switch #3 is for test
VOLTS
purposes. Keep down.
(as shown)
DIP Switch
1
CC Hot Start
Trimmer
2
3
4
High
Setting
"HI" Current Limit
"Lo" Current Limit
Low
Setting
Switch #4 "Hi"CV Current
Limit (as shown)
Note: See Machine Shutdown section
for use of switch #1 and #2.
AMPS
DC-655 Control PC Board
CV OUTPUT
CC MODE ARC FORCE
CC MODE ARC GOUGING
Arc Force provides extra weld current which linearly
increases as the welding voltage decreases below a
level determined by the constant current setting. The
Arc Force control knob, located behind the latched
cover, adjust Arc Force from “Min” (no current
increase) to “Max” (about 9A/V increase).
The DC-655 is rated for air carbon arc gouging with up
to 3/8” (10mm) diameter carbons. CC mode gouging
is often preferred over CV mode for cutting control, but
some Arc Force may be required to avoid carbon stub-
bing.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
Section C-1
Section C-1
TABLE OF CONTENTS
- ACCESSORIES -
Accessories...........................................................................................................................Section C
Field Installed Options................................................................................................................C-2
Connection of Lincoln Electric Automatic or Semiautomatic Wire Feeders..............................C-3
Automatic Wire Feeders.......................................................................................................C-3
NA-3 or LT-7 (Terminal Strip) .........................................................................................C-3
NA-5 or NA-5R (Terminal Strip) .....................................................................................C-4
Semiautomatic Wire Feeders...............................................................................................C-6
LN-7 (14-Pin MS Receptacle)........................................................................................C-6
LN-7 (Terminal Strip)......................................................................................................C-7
LN-8 or LN-9 (Terminal Strip) ........................................................................................C-8
LN-8 or LN-9 (14-Pin MS Receptacle) ..........................................................................C-9
DH-10 (14-Pin MS Receptacle) .....................................................................................C-9
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
C-2
C-2
ACCESSORIES
REMOTE OUTPUT CONTROL
(K775 OR K857 WITH K864 ADAPTER)
FIELD INSTALLED OPTIONS
K1482-1 Digital Ammeter/Voltmeter Kit - Installs
easily to the front control panel and provides digital
display of actual welding voltage and amperage while
welding. (Installation instructions are included with the
kit).
An optional “remote output control” is available. This is
the same remote control that is used on other Lincoln
power sources (K775). The K775 consists of a control
box with 28 ft (8.5m) of four conductor cable. This
connects to terminals 75, 76, and 77 on the terminal
strip and the case grounding screw so marked with the
K1483-1 Analog Ammeter/Voltmeter Kit - Installs
easily to the front control panel and provides analog
display of actual welding voltage and amperage while
welding. (Installation instructions are included with the
kit).
symbol
on the machine. These terminals are locat-
ed behind the cover panel on the lower connection
panel of the DC-655. This control will give the same
control as the output control on the machine.
The K857 has a 6-pin MS-style connector. The K857
requires a K864 adapter cable which connects to the
14-pin connector on the DC-655.
K1484-1 Dual Feeder Kit - This kit replaces the 14-
Pin MS-receptacle panel on the lower case front of the
DC-655. It provides two 14-Pin MS-receptacles and a
built in transfer circuit for connecting and operating
two like-polarity wire feeders. European DC-655 mod-
els can only use 42V feeders with this kit. (Installation
instructions are included with the kit).
REMOTE CONTROL ADAPTER CABLE (K864)
CABLE RECEPTACLE (6 SOCKET)
TO: K857 REMOTE CONTROL
STRAIGHT PLUG (14 PIN)
TO POWER SOURCE
K1485-1 Cable Hanger Bracket - Mounts over stan-
dard lift bale of the DC-655 and provides a cable
hanger on both sides of the power source, each side
capable of holding up to 100 ft. of weld cable.
(Installation instructions are included with the kit).
CABLE RECEPTACLE (14 SOCKET)
TO: LN-7 WIRE FEEDERS
K1486-1 Air Filter Kit - Removable metal filter easily
slides in and out of a bracket which mounts to the
front of the DC-655. Filter is designed to trap 80% of
entering particles which are 5 microns, or larger, in
size. (Installation instructions are included with the kit).
Cannot be used with K1528-1 Dual process switch.
A “V” cable 12” (.30m) long to connect a K857 Remote
Control (6 pin connector) with a wire-feeder (14-pin
connector) and the machine (14-pin connector). If a
remote control is used alone the wire-feeder connec-
tion is then not used.
K1528-1 Dual Process Switch - (Cannot be used with
K1486-1 Air Filter Kit) The Dual-Process Switch
mounts easily to the front of the machine and is
designed to provide a selection between left and right
side output terminals. Each pair of output terminals
can be switched to either the DC-655, high or low
inductance terminals as desired. Wire feed unit cables
and air carbon arc cables can be connected to either
or both sides of the box and with proper connection
can provide polarity change with just a switch change.
Selecting one side only energizes those output studs
and opens the other side. Installation instructions are
included with the switch.)
NOTE: A dirty air filter may cause the thermal protec-
tion of the DC-655 to prematurely activate. Remove
and blow out, or wash and dry, the filter every two
months, or less if in extremely dirty conditions.
Replace if necessary.
Undercarriage (K817P, K842) - The DC-655 is
designed for use with the Lincoln K817P or K842
Undercarriage. Complete installation instructions are
included with each undercarriage. When any of the
undercarriages are installed, the DC-655 lift bail is no
longer functional. Do not attempt to lift the machine
with the undercarriage attached. The undercarriage is
designed for moving the machine by hand only.
Mechanized towing can lead to injury and /or damage
to the DC-655.
K1611-1 Paralleling Kit - Provides interconnection of
two DC-655 machines in parallel for doubling the cur-
rent capacity of one machine. This “master” and
“slave” connection configuration allows the “master”
to control the balanced output of both machines.
Individual protection circuits of both machines func-
tion normally. (Installation instructions are included
with the switch.)
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
C-3
C-3
ACCESSORIES
The DC-655 can be used to power any of
the following Lincoln Wire feeders:
AUTOMATIC WIRE FEEDERS
CONNECTING THE NA-3 OR LT-7 TO THE
IDEALARC DC-655 (TERMINAL STRIP)
SEMI-AUTOMATIC WIRE FEEDERS
1. Set Idealarc DC-655 POWER toggle switch to the
OFF (0) position.
•
•
•
•
•
DH-10
•
•
•
•
•
LN-9*
LN-10
LN-9 GMA*
LN-23P
LN-25
2. Disconnect main AC input power to the Idealarc
DC-655.
LN-7 GMA*
LN-742
LN-7*
3. Connect the wire feeder control cable leads to the
Idealarc DC-655 terminal strip as shown in Figure
C.1.
LN-8*
4. Connect the wire feeder control cable ground lead
to the frame terminal marked
.
AUTOMATIC WIRE FEEDERS*
NOTE: The Idealarc DC-655 must be properly
•
•
NA-3
NA-5
•
•
NA-5R
LT-7 Tractor
grounded.
* European DC-655 models only provide 115VAC for these feeders at the ter-
minal strip (TS2)
FIGURE C.1 – NA-3 OR LT-7 WIRE FEEDER
CONNECTION TO THE IDEALARC DC-655
14-PIN
RECEPTACLE
CONNECTION OF LINCOLN ELECTRIC
AUTOMATIC OR SEMIAUTOMATIC WIRE
FEEDERS
POWER SOURCE
CONTROL CABLE
FOR CONTROL CABLE
WITH 14 PIN
MS-TYPE
PLUG CONNECTOR
TO AUTOMATIC
CONTROL BOX
21
OR
CONTROL CABLE
WARNING
FOR CONTROL CABLE
WITH TERMINAL STRIP
LEAD CONNECTORS
ELECTRIC SHOCK can kill.
+
21
-
21 41
75 76
77
4
2
31 32
• Only qualified personnel should per-
form this installation.
77
76
75
32
31
2
4
• Turn the input power OFF at the dis-
connect switch or fuse box before working on this
equipment.
GND
21
NEGATIVE
POSITIVE
• Do not touch electrically hot parts.
ELECTRODE CABLE
TO AUTOMATIC
EQUIPMENT
Auxiliary power for wire feeder operation is available at
both a 14-pin MS receptacle and at terminal strips
with screw-type connections located on the front of
the machine. Refer to the Installation section for
pinouts and lead designations. The two circuits are
isolated, and each is protected by a circuit breaker.
TO WORK
REMOTE VOLTAGE SENSING LEAD
5. Extend wire feeder control cable lead #21 so it can
be connected directly to the work piece.
a. Make a bolted connection using AWG #14 or
larger insulated wire. Tape the bolted connec-
tion with insulating tape.
The following descriptions show how to connect the
wire feeders using either the 14-pin MS receptacle or
the terminal strip.
b. An S-16586- X remote voltage sensing work
lead is available for this purpose.
c. Keep the #21 lead electrically separate from
the work cable circuit and connection.
d. Tape the #21 lead to work cable for ease of
use.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
C-4
C-4
ACCESSORIES
NOTE: The connection diagram shown in Figure C.1
shows the electrode connected for positive
polarity. To change polarity:
FIGURE C.2 – NA-5/-5R WIRE FEEDER
CONNECTION TO THE IDEALARC DC-655
14-PIN
RECEPTACLE
a. Set the Idealarc DC-655 POWER toggle
switch to the OFF (0) position.
POWER SOURCE
CONTROL CABLE
FOR CONTROL CABLE
WITH 14 PIN
MS-TYPE
PLUG CONNECTOR
b. Move the electrode cable to the negative (-)
output terminal. (High inductance or low
inductance, as needed).
21
TO NA-5/-5R
INPUT CABLE PLUG
OR
FOR CONTROL CABLE
WITH TERMINAL STRIP
LEAD CONNECTORS
CONTROL CABLE
c. Move the work cable to the positive (+) output
terminal.
+
21
-
21 41
75 76
77
4
2
31 32
d. If connecting lead #21 to the terminal strip,
connect it to the +21 terminal (to match work
polarity). If work polarity changes back to
negative, lead #21 must be connected to the
-21 terminal.
C
B
A
32
31
2
4
GND
NEGATIVE
POSITIVE
21
e. Reverse the leads on the back of the ammeter
and voltmeter in the automatic control box.
BOLT TO CABLES FROM NA-5/-5R
WIRE CONTACT AS'BLY
f. If the automatic controls include a variable
voltage board, connect its jumper lead to pin
“L”. This will permit the inch down button to
operate. However, the jumper also disables
the cold starting/autostop feature of the auto-
matic controls. Only hot starting will be avail-
able.
TO WORK
REMOTE VOLTAGE SENSING LEAD
4. Connect the wire feeder control cable ground lead
to the frame terminal marked
.
6. Set the DC-655 OUTPUT CONTROL switch to the
“Remote” position and the OUTPUT TERMINALS
switch in the “Remote” position.
NOTE: The Idealarc DC-655 must be properly
grounded.
5. Extend wire feeder control cable lead #21 so it can
be connected directly to the work piece.
CONNECTING THE NA-5/-5R TO THE
IDEALARC DC-655 (TERMINAL STRIP)
a. Make a bolted connection using AWG #14 or
larger insulated wire. Tape the bolted connec-
tion with insulating tape.
1. Set the Idealarc DC-655 POWER toggle switch to
the OFF (0) position.
b. An S-16586-X remote voltage sensing work
lead is available for this purpose.
2. Disconnect main AC input power to the Idealarc
DC-655.
c. Keep the #21 lead electrically separate from
the work cable circuit and connection.
3. Connect the wire feeder control cable leads to the
Idealarc DC-655 terminal strip as shown in Figure
C.2.
d. Tape the #21 lead to work cable for ease of
use.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
C-5
C-5
ACCESSORIES
6. Connect NA-5/-5R wire feeder control jumpers on
Voltage Control Board. See NA-5/-5R Operator’s
Manual.
NOTE: The connection diagram shown in Figure C.2
shows the electrode connected for positive
polarity. To change polarity:
a. Set the Idealarc DC-655 POWER toggle
switch to the OFF (0) position.
b. Move the electrode cable to the negative (-)
output terminal. (High inductance or low
inductance as needed).
c. Move the work cable to the positive (+) output
terminal.
d. If connecting lead #21 to the terminal strip,
connect it to the +21 terminal (to match work
polarity). If work polarity changes back to
negative, lead #21 must be connected to the -
21 terminal.
NOTE: For proper NA-5 operation, the electrode
cables must be secured under the clamp bar
on the left side of the NA-5 Control Box.
7. Set the DC-655 OUTPUT CONTROL switch to the
“Remote” position and the OUTPUT TERMINALS
switch to the “Remote” position.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
C-6
C-6
ACCESSORIES
FIGURE C.3
IDEALARC DC-655/LN-7 WITH K584 INPUT CABLE ASSEMBLY CONNECTION DIAGRAM
POWER SOURCE
LN-7 TO INPUT
CABLE PLUG
21
LN-7 CONTROL
CABLE
+
21
-
21 41
75 76
77
4
2
31 32
32
31
2
4
GND
NEGATIVE
POSITIVE
21
ELECTRODE CABLE
TO WIRE FEED UNIT
TO WORK
}
REMOTE VOLTAGE SENSING LEAD
SEMIAUTOMATIC WIRE FEEDERS
CONNECTING THE LN-7 TO THE IDEALARC
DC-655 (14-PIN MS RECEPTACLE)
1. Set the POWER toggle switch to the OFF (0) posi-
tion.
4. Connect control cable between the DC-655 and
the LN-7. See Figure C.3.
2. Disconnect main AC input power to the Idealarc
DC-655.
5. Set the MODE switch to a CV (constant voltage)
position at the welder.
3. Connect the electrode cable from the control
cable to the “+” terminal of the welder and to the
LN-7 wire feeder. Connect the work cable to the
“-” terminal of the welder (High inductance or low
inductance as needed). Reverse this hookup for
negative polarity.
6. Adjust wire feed speed at the LN-7 and set the
welding voltage with the output CONTROL.
NOTE: If optional remote control is used, place the
OUTPUT CONTROL and the OUTPUT TERMI-
NALS switch in the “Remote” position.
NOTE: Welding cable must be sized for the current
and duty cycle of the application.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
C-7
C-7
ACCESSORIES
CONNECTING THE LN-7 TO THE
IDEALARC DC-655 (TERMINAL STRIP)
NOTE: If the work cable length is less than 25 feet
and the connections to the work piece are
secure, then wire feeder control cable lead
#21 can be connected directly to the DC-
655 terminal strip.
1. Set the Idealarc DC-655 POWER toggle switch to
the OFF (0) position.
2. Disconnect main AC input power to the Idealarc
DC 655.
b. An S-16586-X remote voltage sensing work
lead is available for this purpose.
3. Connect the wire feeder control cable leads to the
Idealarc DC-655 terminal strip as shown in Figure
C.3.
c. Keep the #21 lead electrically separate from
the work cable circuit and connection.
d. Tape the #21 lead to work cable for ease of
use.
4. Connect the wire feeder control cable ground lead
to the frame terminal marked
.
NOTE: The connection diagram shown in Figure
C.3 shows the electrode connected for
positive polarity. To change polarity:
NOTE: The Idealarc DC-655 must be properly
grounded.
5. PERFORM THIS STEP ONLY IF THE LN-7 IS
EQUIPPED WITH A METER KIT.
a. Set the IDEALARC DC-655 POWER toggle
switch to the OFF (0) position.
Extend wire feeder control cable lead #21 so it can
be connected directly to the work piece.
b. Move the electrode cable to the negative (-)
output terminal (High inductance or low induc-
tance as needed).
a. Make a bolted connection using AWG #14 or
larger insulated wire. Tape the bolted connec-
tion with insulating tape.
c. Move the work cable to the positive (+) output
terminal.
d. Connect control cable lead #21 to “+21” on
the terminal strip.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
C-8
C-8
ACCESSORIES
FIGURE C.4 - LN-8 OR LN-9 WIRE FEEDER CONNECTION TO THE IDEALARC DC-655
POWER SOURCE
21
TO LN-8 OR LN-9
INPUT CABLE PLUG
CONTROL CABLE
+
21
-
21 41
75 76
77
4
2
31 32
C
B
N.E.
}
A
32
31
2
4
GND
21
NEGATIVE
POSITIVE
ELECTRODE CABLE
TO WIRE FEED UNIT
TO WORK
}
REMOTE VOLTAGE SENSING LEAD
CONNECTING THE LN-8 OR LN-9 TO THE
IDEALARC DC-655 (TERMINAL STRIP)
6. Connect LN-9 wire feeder control jumpers on
Voltage Control board. See LN-9 Operator’s
Manual.
1. Set the Idealarc DC-655 POWER toggle switch to
the OFF (0) position.
NOTE: The connection diagram shown in Figure C.4
shows the electrode connected for positive
polarity. To change polarity:
2. Disconnect main AC input power to the Idealarc
DC-655.
a. Set the Idealarc DC-655 POWER toggle
switch to the OFF (0) position.
3. Connect the wire feeder control cable leads to the
Idealarc DC-655 terminal strip as shown in Figure
C.4.
b. Move the electrode cable to the negative (-)
output terminal (High inductance or low
inductance as needed).
4. Connect the wire feeder control cable ground lead
to the frame terminal marked
.
c. Move the work cable to the positive (+) output
terminal.
5. Extend wire feeder control cable lead #21 so it can
be connected directly to the work piece.
d. Connect control cable lead #21 to “+21” on
the terminal strip.
a. Make a bolted connection using AWG #14 or
larger insulated wire. Tape the bolted connec-
tion with insulating tape.
7. Set the OUTPUT CONTROL switch to the
“Remote” position and the OUTPUT TERMINALS
switch to the “Remote” position.
b. An S-16586- X remote voltage sensing work
lead is available for this purpose.
c. Keep the #21 lead electrically separate from
the work cable circuit and connection.
d. Tape the #21 lead to work cable for ease of
use.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
C-9
C-9
ACCESSORIES
CONNECTING THE LN-8 OR LN-9 TO THE
IDEALARC DC-655 (14-PIN MS RECEPTACLE)
CONNECTING THE DH-10 TO THE
IDEALARC DC-655 (14-PIN MS RECEPTACLE)
1. Set the POWER toggle switch to the OFF (0) posi-
tion.
1. Set the POWER toggle switch to the OFF (0) posi-
tion.
2. Disconnect main AC input power to the Idealarc
DC-655.
2. Disconnect main AC input power to the Idealarc
DC-655.
3. Connect the electrode cable from the LN-8 or
LN-9 to the “+” terminal of the welder. Connect
the work cable to the “-” terminal of the welder
(High inductance or low inductance as needed).
Reverse this hookup for negative polarity. See
Figure C.4.
3. Connect the electrode cable from the DH-10 to the
“+” terminal of the welder. Connect the work
cable to the “-” terminal of the welder (High induc-
tance or low inductance as needed). Reverse this
hookup for negative polarity.
NOTE: Welding cable must be sized for the current
NOTE: Welding cable must be sized for the current
and duty cycle of the application.
and duty cycle of the application.
4. Connect the DH-10 input cable between the 14-
pin MS receptacle on the DC-655 and the input
cable plug on the DH-10. See Figure C.5.
4. Connect the control cable between the 14-pin MS
receptacle on the DC-655 and the input cable plug
on the LN-8 or LN-9. See Figure C.4.
5. Set the MODE switch to a CV (constant voltage)
position.
5. Set the MODE switch to a CV (constant voltage)
position.
6. Adjust wire feed speed at the DH-10 and set the
welding voltage with the WIRE FEEDER VOLTAGE
CONTROL.
6. Adjust wire feed speed at the LN-8 or LN-9 and
set the welding voltage with the WIRE FEEDER
VOLTAGE CONTROL.
7. Set the DIP switches on the DH-10 for DC-655.
See the DH-10 Operator’s Manual.
Place the OUTPUT CONTROL switch in the “Remote”
position and the OUTPUT TERMINALS switch in the
“Remote” position.
Place the OUTPUT CONTROL switch in the “Remote”
position and the OUTPUT TERMINALS switch in the
“Remote” position.
FIGURE C.5 – IDEALARC DC-655 DH-10 CONNECTION
DH-10
WIRE
FEEDER
LINCOLN CV-655
POWER SOURCE
N.E.
+
-
9 PIN
AMPHENOL
14 PIN
AMPHENOL
ELECTRODE CABLE
TO WORK
DH-10
INPUT CABLE
ASSEMBLY
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
NOTES
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
Section D-1
Section D-1
TABLE OF CONTENTS
-MAINTENANCE-
Maintenance .........................................................................................................................Section D
Safety Precautions......................................................................................................................D-2
General Maintenance..................................................................................................................D-2
General Component Locations...................................................................................................D-3
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
D-2
D-2
MAINTENANCE
SAFETY PRECAUTIONS
WARNING
ELECTRIC SHOCK can kill.
• Only qualified personnel should per-
form this maintenance.
• Turn the input power OFF at the disconnect switch
or fuse box before working on this equipment.
• Do not touch electrically hot parts.
GENERAL MAINTENANCE
1. The fan motor has sealed bearings which require
no service.
2. In extremely dusty locations, dirt may restrict the
cooling air causing the welder to run hot with pre-
mature tripping of thermal protection. Blow ou;the
welder with low pressure air at regular intervals to
eliminate excessive dirt and dust build-up on inter-
nal parts.
3. Periodically check the welding cables. Inspect for
any slits or punctures. Also make sure that all
connections are tight.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
D-3
D-3
MAINTENANCE
FIGURE D.1 - GENERAL COMPONENT LOCATIONS
1. CASE FRONT
2. OUTPUT TERMINALS
3. CASE SIDES
4. CASE TOP
5. RECONNECT PANEL (LOCATION)
6. INPUT CONTACTOR (LOCATION)
7. CONTROL TRANSFORMER (LOCATION)
8. CASE BACK
9. FAN ASSEMBLY
10. CONTROL PANEL
11. PC BOARDS (LOCATION)
12. CHOKE
13. MAIN TRANSFORMER
14. BASE
15. SCR RECTIFIER BRIDGE
4
3
5
6
7
8
DC-655
11
10
9
DC-655
2
1
3
15
12
14
13
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
NOTES
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
Section E-1
Section E-1
TABLE OF CONTENTS
-THEORY OF OPERATION SECTION-
Theory of Operation .............................................................................................................Section E
General Description ....................................................................................................................E-2
Input Line Voltage, Contactor, Reconnect,
Fault Protection, Main and Control Transformers.......................................................................E-2
Control Board, Firing Board, Snubber/Fan
Board and Rectification ..............................................................................................................E-3
Protective Devices and Shutdown Circuits ................................................................................E-4
Thermal Protection ...............................................................................................................E-4
Over Current Protection .......................................................................................................E-4
Peak Current Protection.......................................................................................................E-4
Remote Control Fault Protection..........................................................................................E-4
Shorted Output Rectifier Fault Protection............................................................................E-4
SCR Operation............................................................................................................................E-5
FIGURE E.1 – DC-655 BLOCK LOGIC DIAGRAM
CONTROL
TRANSFORMER
42VAC
115VAC
CONTROL
BOARD
TRANSFORMER
FAULT PROTECTION
CR2
OUTPUT
CONTROL
ARC FORCE
CONTROL
OUTPUT
CONTROL SIGNAL
32VAC
32VAC
32VAC
FIRING
BOARD
S
I
G
N
A
L
G
A
T
Fan
Motor
14-pin
115VAC
Amphenol Receptacle
Fan
Thermal
Sensor
E
CONTROL
BOARD
SNUBBER
FAN
BOARD
T
S
E
MODE
SWITCH
T
R
115VAC
R
I
P
M
I
N
A
L
SIGNAL
GATE
F
42VAC
E
E
D
B
A
C
K
MAIN
TRANSFORMER
R
E
C
POSITIVE
TERMINAL
O
N
N
E
C
T
SHUNT
F
E
E
D
B
A
C
LATCHING
RESISTOR
10VAC
42VAC 10VAC
CONTACTOR
CR1
SCR BRIDGE
HIGH
NEGATIVE
TERMINAL
CHOKE
K
TO OPTIONAL
METER BOARD
LOW
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
E-2
E-2
THEORY OF OPERATION
FIGURE E.2 – INPUT LINE VOLTAGE, CONTACTOR, RECONNECT,
FAULT PROTECTION, MAIN AND CONTROL TRANSFORMERS
CONTROL
TRANSFORMER
42VAC
115VAC
CONTROL
BOARD
TRANSFORMER
FAULT PROTECTION
CR2
OUTPUT
CONTROL
ARC FORCE
CONTROL
OUTPUT
CONTROL SIGNAL
32VAC
32VAC
32VAC
FIRING
BOARD
S
I
G
N
A
L
G
A
T
Fan
Motor
14-pin
115VAC
Amphenol Receptacle
Fan
Thermal
Sensor
E
CONTROL
BOARD
SNUBBER
FAN
BOARD
T
S
E
MODE
SWITCH
T
R
115VAC
R
I
P
M
I
N
A
L
SIGNAL
GATE
F
42VAC
E
E
D
B
A
C
K
MAIN
TRANSFORMER
R
E
C
POSITIVE
TERMINAL
O
N
N
E
C
T
SHUNT
F
E
E
D
B
A
C
K
LATCHING
RESISTOR
10VAC
42VAC 10VAC
CONTACTOR
CR1
SCR BRIDGE
HIGH
NEGATIVE
TERMINAL
CHOKE
TO OPTIONAL
METER BOARD
LOW
A reconnect panel allows the user to configure the
machine for the desired input voltage. This three-
phase AC input is applied to the primary of the main
transformer. The transformer changes the high volt-
age, low current input power to a lower voltage, high-
er current output. The finishes or “neutrals” of the
main secondary coils are connected together, and the
six starts of the secondary windings are connected to
the rectifier assembly.
GENERAL DESCRIPTION
The DC-655 is a three-phase, SCR controlled DC
power source. It is capable of either constant current
or constant voltage output. It is rated at 650 amps,
100% duty cycle with outstanding arc characteristics
for multiple welding processes.
In addition, the main transformer also has eight isolat-
ed secondary windings. There are three 32 VAC wind-
ings, which provide power and “timing” to the firing
board. The 115 VAC winding powers the fan motor
and provides the user with up to 20 amps of 115 VAC
auxiliary power at the receptacle or 14-pin MS type
connector. The 42 VAC winding provides up to 10
amps at the 14-pin MS type connector. Three other
isolated coils are used to power the optional digital
meter PC board. One winding is rated at 42 VAC, and
the other two are each rated at 10 VAC.
INPUT LINE, CONTACTOR,
RECONNECT, FAULT PROTECTION
AND TRANSFORMERS
The desired three-phase input power is connected to
the DC-655 through an input contactor located in the
input box at the rear of the machine. Two phases of
the input line are also connected to the control trans-
former. The secondary of the control transformer sup-
plies 115 VAC power to the control board transformer
and to the input contactor through the fault protection
relay. The control board transformer supplies 42 VAC
to the control board.
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
E-3
E-3
THEORY OF OPERATION
FIGURE E.3 – CONTROL BOARD, FIRING BOARD, SNUBBER/FAN BOARD AND RECTIFICATION
CONTROL
TRANSFORMER
42VAC
115VAC
CONTROL
BOARD
TRANSFORMER
FAULT PROTECTION
CR2
OUTPUT
ARC FORCE
CONTROL
OUTPUT
CONTROL SIGNAL
32VAC
32VAC
32VAC
CONTROL
FIRING
BOARD
S
I
G
N
A
L
G
A
T
Fan
Motor
14-pin
115VAC
Amphenol Receptacle
Fan
Thermal
Sensor
E
CONTROL
BOARD
SNUBBER
FAN
BOARD
T
S
E
MODE
SWITCH
T
R
115VAC
R
I
P
M
I
N
A
L
SIGNAL
GATE
F
42VAC
E
E
D
B
A
C
K
MAIN
TRANSFORMER
R
E
C
POSITIVE
TERMINAL
O
N
N
E
C
T
SHUNT
F
E
E
D
B
A
C
LATCHING
RESISTOR
10VAC
42VAC 10VAC
CONTACTOR
CR1
SCR BRIDGE
HIGH
NEGATIVE
TERMINAL
CHOKE
K
TO OPTIONAL
METER BOARD
LOW
tion from the shunt and voltage feedback information
from the choke and welding output terminals. This
feedback information is processed on the control
board. The control compares the commands of the
mode switch, the output control potentiometer (or
remote control device) and the arc force control with
the feedback information and sends the appropriate
output control signal to the firing board. In the event
of a “fault condition,” the control board activates the
fault relay (CR2). See Protective Devices and Shut
Down Circuits.
CONTROL BOARD, FIRING BOARD,
SNUBBER/FAN, BOARD AND
RECTIFICATION
The “neutrals” of the welding secondary windings in
the main transformer are connected together, and the
six starts are connected to the six Silicon Controlled
Rectifier (SCR) assemblies to form a six-phase output.
This six-phase AC output from the main transformer
secondary is rectified and controlled through the SCR
bridge.
A tapped output choke is connected between the neu-
tral connection of the main transformer secondaries
and the two negative output terminals. This large
inductor stores energy, which provides current filtering
for the welding output of the DC-655. Two negative
output terminals are provided. One is connected to
the tap lead in the choke, thus providing a lower induc-
tance. The other utilizes the entire choke for higher
inductance arc characteristics.
A portion of the firing board is a three-phase circuit.
Each phase provides two firing pulses, one for each of
the two SCRs controlled by that phase. When a gate
firing enable signal is received, the firing circuit sup-
plies the proper amount of energy to the gates of the
power SCRs. When this gate firing signal is applied at
the correct time, through the snubber/fan board, the
SCR will turn ON. The amount of ON time versus OFF
time determines the output of the machine. See SCR
Operation. At this time the latching resistor is brought
into the machine’s output circuit. The latching resistor
provides a pre-load for the SCR bridge.
The snubber/fan board furnishes protection to the
SCR bridge from the transient voltages. It also moni-
tors the thermal sensor and activates the fan motor
when cooling is necessary.
The control board receives current feedback informa-
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
E-4
E-4
THEORY OF OPERATION
PROTECTIVE DEVICES AND
SHUTDOWN CIRCUITS
THERMAL PROTECTION
PEAK CURRENT PROTECTION
Two thermostats protect the DC-655 from excessive
operating temperatures. Excessive operating temper-
atures may be caused by a lack of cooling air or oper-
ating the machine beyond the duty cycle and output
rating. If excessive operating temperatures should
occur, a thermostat will open. This condition will be
indicated by the illumination of the yellow
Thermostatic Protection Light located on the case
front. The fan should continue to run, but the welding
output will be disabled until the machine cools and the
Thermostatic Protection Light is out.
If the peak current exceeds 2500 amps, the welding
output will be disabled and the control board LED 4
shutdown light will turn on. The peak current shut-
down circuit can be reset by turning the DC-655 input
switch off.
REMOTE CONTROL FAULT PROTECTION
The remote control leads from the 14-pin receptacles
or terminal strip are protected against voltage faults to
the electrode circuit or auxiliary voltage supplies. If a
fault should occur, the welding output will be disabled
and the control board LED 4 shutdown light will turn
on. This fault protection shutdown circuit can be reset
by opening the feeder gun trigger or switching the DC-
655 output terminal switch to the OFF position. On
later production machines, LED 3 input shutdown light
will turn on and the input contactor will open.
OVER CURRENT PROTECTION
If the average output current exceeds 900 amps for
five to six seconds, the welding output will be dis-
abled. The control board LED 4 shutdown light will
turn on. The higher the current, the quicker the DC-
655 will shut down. If the average current exceeds
1200 amps, the shutdown will occur in 0.3 seconds.
The over current shutdown circuit can be reset by
opening the feeder gun trigger or switching the DC-
655 output terminal switch to the OFF position.
SHORTED OUTPUT RECTIFIER FAULT
PROTECTION
If a short should occur across one of the SCRs, a
potentially hazardous AC voltage could appear across
the welding output terminals. If such a fault should
occur, the input contactor will open and remove the
input power to the primary of the main transformer.
Also, the control board LED 3 input shutdown light will
turn on. Welding and auxiliary output will not be pre-
sent, but the pilot light and control board power will be
present until the power switch is turned off.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
E-5
E-5
THEORY OF OPERATION
FIGURE E.4 – SCR OPERATION
SCR OPERATION
A silicon controlled rectifier (SCR) is a three-terminal
device used to control rather large currents to a load.
An SCR acts very much like a switch. When a gate
signal is applied to the SCR, it is turned ON and there
is current flow from anode to cathode. In the ON state
the SCR acts like a closed switch. When the SCR is
turned OFF, there is no current flow from anode to
cathode. Thus the device acts like an open switch.
As the name suggests, the SCR is a rectifier, so it
passes current only during positive half cycles of the
AC supply. The positive half cycle is the portion of the
sine wave in which the anode of the SCR is more pos-
itive than the cathode.
An SCR is fired by a short burst of current into the
gate. This gate pulse must be more positive than the
cathode voltage. Since there is a standard PN junc-
tion between gate and cathode, the voltage between
these terminals must be slightly greater than 0.6V .
Once the SCR has fired, it is not necessary to contin-
ue the flow of gate current. As long as current contin-
ues to flow from anode to cathode, the SCR will
remain on. When the anode to cathode current drops
below a minimum value, called holding current, the
SCR will shut off. This normally occurs as the AC sup-
ply voltage passes through zero into the negative por-
tion of the sine wave. If the SCR is turned on early in
the positive half cycle, the conduction time is longer,
resulting in greater SCR output. If the gate firing
occurs later in the cycle, the conduction time is less,
resulting in lower SCR output.
When an AC supply voltage is applied to the SCR, the
device spends a certain portion of the AC cycle time
in the ON state and the remainder of the time in the
OFF state. The amount of time spent in the ON state
is controlled by the Gate.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
NOTES
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
Section F-1
Section F-1
TABLE OF CONTENTS
TROUBLESHOOTING & REPAIR SECTION
Troubleshooting & Repair Section.................................................................................Section F
How to Use Troubleshooting Guide ......................................................................................F-2
PC Board Troubleshooting Procedures.................................................................................F-3
Troubleshooting Guide .................................................................................................F-4–F-12
Test Procedures
Internal Trigger Circuit Test ...........................................................................................F-13
Firing Board Test ...........................................................................................................F-17
Main Transformer (T1) Voltage Test...............................................................................F-22
Control Transformer (T2) Voltage Test...........................................................................F-27
Control Board Transformer (T3) Test.............................................................................F-30
Input Contactor Test......................................................................................................F-32
Static SCR Test .............................................................................................................F-35
Active SCR Test.............................................................................................................F-38
Thermal Fan/Snubber Board LED Chart.......................................................................F-41
Control Board LED Chart ..............................................................................................F-42
Oscilloscope Waveforms
Normal Open Circuit Voltage Waveform-Constant Current Mode................................F-43
Normal Open Circuit Voltage Waveform-Constant Voltage MIG Maximum Output.....F-44
Normal Open Circuit Voltage Waveform-Constant Voltage MIG Minimum Output......F-45
Typical Output Voltage Waveform-Constant Voltage MIG............................................F-46
Typical SCR Gate Voltage Waveform-Constant Voltage MIG.......................................F-47
Abnormal Open Circuit Voltage Waveform-Constant Voltage MIG ..............................F-48
Replacement Procedures
Input Contactor (CR1) Cleaning/Replacement .............................................................F-49
SCR Rectifier Bridge Removal and Replacement ........................................................F-51
Main Transformer and Choke Removal and Replacement...........................................F-54
Retest After Repair ..............................................................................................................F-57
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-2
F-2
TROUBLESHOOTING & REPAIR
HOW TO USE TROUBLESHOOTING GUIDE
WARNING
Service and repair should be performed by only Lincoln Electric Factory Trained Personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician and machine
operator and will invalidate your factory warranty. For your safety and to avoid Electrical Shock, please
observe all safety notes and precautions detailed throughout this manual.
This Troubleshooting Guide is provided to help
you locate and repair possible machine malfunc-
tions. Simply follow the three-step procedure
listed below.
Step 3. PERFORM COMPONENT TESTS. The
last column, labeled “Recommended Course of
Action” lists the most likely components that may
have failed in your machine. It also specifies the
appropriate test procedure to verify that the sub-
ject component is either good or bad. If there are
a number of possible components, check the
components in the order listed to eliminate one
possibility at a time until you locate the cause of
your problem.
Step 1. LOCATE PROBLEM (SYMPTOM). Look
under the column labeled “PROBLEM (SYMP-
TOMS). This column describes possible symp-
toms that the machine may exhibit. Find the list-
ing that best describes the symptom that the
machine is exhibiting. Symptoms are grouped
into three main categories: Output Problems,
Function Problems and Welding Problems.
All of the referenced test procedures referred to in
the Troubleshooting Guide are described in detail
at the end of this chapter. Refer to the
Troubleshooting and Repair Table of Contents to
locate each specific Test Procedure. All of the
referred to test points, components, terminal
strips, etc., can be found on the referenced elec-
trical wiring diagrams and schematics. Refer to
the Electrical Diagrams Section Table of Contents
to locate the appropriate diagram.
Step 2. PERFORM EXTERNAL TESTS. The
second column, labeled “POSSIBLE AREAS OF
MISADJUSTMENT(S)”, lists the obvious external
possibilities that may contribute to the machine
symptom. Perform these tests/checks in the
order listed. In general, these tests can be con-
ducted without removing the case wrap-around
cover.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs
safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before
you proceed. Call 1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-3
F-3
TROUBLESHOOTING & REPAIR
PC BOARD TROUBLESHOOTING PROCEDURES
- Remove the PC board from the static-shielding bag
and place it directly into the equipment. Don’t set the
PC board on or near paper, plastic or cloth which
could have a static charge. If the PC board can’t be
installed immediately, put it back in the static-shield-
ing bag.
WARNING
ELECTRIC SHOCK
can kill.
•
Have an electrician install and
service this equipment. Turn the
input power OFF at the fuse box
before working on equipment. Do
not touch electrically hot parts.
- If the PC board uses protective shorting jumpers,
don’t remove them until installation is complete.
- If you return a PC board to The Lincoln Electric
Company for credit, it must be in the static-shielding
bag. This will prevent further damage and allow prop-
er failure analysis.
CAUTION
Sometimes machine failures appear to be due to PC
board failures. These problems can sometimes be
traced to poor electrical connections. To avoid prob-
lems when troubleshooting and replacing PC boards,
please use the following procedure:
4. Test the machine to determine if the failure
symptom has been corrected by the
replacement PC board.
NOTE: It is desirable to have a spare (known good)
PC board available for PC board troubleshooting.
1. Determine to the best of your technical ability
that the PC board is the most likely component
causing the failure symptom.
NOTE: Allow the machine to heat up so that all
electrical components can reach their operating
temperature.
2. Check for loose connections at the PC board to
assure that the PC board is properly connected.
5. Remove the replacement PC board and
substitute it with the original PC board to
recreate the original problem.
3. If the problem persists, replace the suspect PC
board using standard practices to avoid static
electrical damage and electrical shock. Read
the warning inside the static resistant bag and
perform the following procedures:
a. If the original problem does not reappear by
substituting the original board, then the PC
board was not the problem. Continue to look
for bad connections in the control wiring
harness, junction blocks, and terminal strips.
PC board can be damaged by static electricity.
b. If the original problem is recreated by the
substitution of the original board, then the PC
board was the problem. Reinstall the
replacement PC board and test the machine.
- Remove your body’s static
charge before opening the static-
shielding bag. Wear an anti-static
wrist strap. For safety, use a 1
Meg ohm resistive cord connected
6. Always indicate that this procedure was
followed when warranty reports are to be
submitted.
to
a
grounded part of the
equipment frame.
ATTENTION
Static-Sensitive
Devices
Handle only at
Static-Safe
- If you don’t have a wrist strap,
touch an un-painted, grounded,
part of the equipment frame. Keep
touching the frame to prevent
static build-up. Be sure not to
touch any electrically live parts at
the same time.
NOTE: Following this procedure and writing on the
warranty report, “INSTALLED AND SWITCHED PC
BOARDS TO VERIFY PROBLEM,” will help avoid
denial of legitimate PC board warranty claims.
Workstations
- Tools which come in contact with the PC board must
be either conductive, anti-static or static-dissipative.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-4
F-4
TROUBLESHOOTING & REPAIR
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
POSSIBLE AREAS OF
MISADJUSTMENT(S)
RECOMMENDED
COURSE OF ACTION
OUTPUT PROBLEMS
Major physical or electrical dam- 1. Contact the Lincoln Electric
age is evident. Service Dept. 1-800-833-9353.
The machine is dead - the input 1. The power switch (S1) is in the 1. Check the power switch (S1)
contactor does not operate. The
pilot light is not lit.
ON position.
and associated leads and con-
nections.
See the Wiring
2. Check for blown or missing
fuses in the input lines.
Diagram.
2. Perform the Control Trans-
3. Check the three-phase input
line voltage at the machine.
The input voltage must match
the rating plate and reconnect
panel.
former Test.
The input contactor operates, but 1. Check the electrode and work 1. Perform the Internal Trigger
no welding output. The 115 VAC
auxiliary supply is present at the
receptacle.
cables for loose or faulty con-
nections.
Circuit Test.
2. Perform the Firing Board Test.
2. If the Thermal Protection Light
is ON, the machine is overheat-
ed. Wait for the machine to
3. Perform the Main Transformer
Test.
cool and remedy the cause of 4. Perform the SCR Output
the overheating problem. See
the Fan/Snubber Board LED
Chart.
Bridge Test.
5. The control board may be
faulty. See Control Board LED
Chart.
3. Make certain either the output
terminals switch is in the ON
position or the external gun
trigger circuit is functioning
properly.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-5
F-5
TROUBLESHOOTING & REPAIR
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
POSSIBLE AREAS OF
MISADJUSTMENT(S)
RECOMMENDED
COURSE OF ACTION
OUTPUT PROBLEMS
The input contactor chatters.
1. Check the three-phase input 1. Check for loose or faulty wiring
line voltage at the machine.
The input voltage must match
the rating plate and reconnect
panel configuration.
between the input power
switch (SW1), the fault protec-
tion relay (CR2) and the input
contactor.
Diagram.
See the Wiring
2. The fault protection relay (CR2)
may have defective contacts.
Check or replace.
3. The control board may be
defective. See the Control
Board LED Chart.
4. The input contactor may be
faulty.
The machine is dead - the input 1. Check the three-phase input 1. Check the wiring between the
contactor does not operate. The
pilot light is lit.
line voltage at the machine.
The input voltage must match
the rating plate and reconnect
panel configuration.
fault protection relay (CR2) and
the input contactor (CR1).
2. The fault protection relay (CR2)
may have defective contacts.
Check or replace.
2. Turn the machine off and then
back on to reset the fault pro-
tection circuit. See the Control
Board LED Chart.
3. The input contactor may be
faulty.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-6
F-6
TROUBLESHOOTING & REPAIR
TROUBLESHOOTING GUIDE
Observe Safety Guidelines
detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
POSSIBLE AREAS OF
MISADJUSTMENT(S)
RECOMMENDED
COURSE OF ACTION
OUTPUT PROBLEMS
The machine has welding output 1. Check the output control switch 1. The output control potentiome-
but no control.
(SW3) for proper setting.
ter, output control switch (SW3)
or associated wiring may be
2. If a remote control cable is
used, make certain the cable
and connections are good.
defective.
Diagram.
See the Wiring
2. Perform the Firing Board Test.
3. Perform the SCR Output
Bridge Test.
4. The control board may be
faulty. See the Control Board
LED Chart.
The machine does not have maxi- 1. Check the three-phase input 1. The output control potentiome-
mum output.
lines at the DC-655. Make cer-
tain the input voltages match
the machine’s rating and recon-
nect panel configuration.
ter, output control switch (SW3)
or associated wiring may be
defective.
Diagram.
See the Wiring
2. Put the output control switch 2. Perform the Main Transformer
(SW3) in the “Local” control
position. If the problem is
resolved, the remote unit or
wire feeder may be defective.
Test.
3. Perform the Firing Board Test.
4. Perform the SCR Bridge Test.
5. The control board may be
faulty. See the Control Board
LED Chart.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-7
F-7
TROUBLESHOOTING & REPAIR
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
detailed in the beginning of this manual.
PROBLEMS
POSSIBLE AREAS OF
RECOMMENDED
(SYMPTOMS)
MISADJUSTMENT(S)
COURSE OF ACTION
OUTPUT PROBLEMS
The 115 VAC receptacle is not 1. The circuit breaker may be 1. The circuit breaker may be
working. The machine’s welding
output is normal.
tripped. Reset if necessary.
defective. Check associated
wiring. See the Wiring Diagram.
2. Make sure the 115 VAC plug
and “load” is in good working 2. Check for 115 VAC at terminals
condition.
#31 and #32 on the terminal
strip. If 115 VAC is present at
the terminal strip, check the
wiring between the terminal
stirp, the circuit breaker and the
115 VAC receptacle. If 115 VAC
is NOT present at the terminal
strip, perform the Main
Transformer Test.
3. The 115 VAC receptacle may
be defective.
When not welding for a period of 1. This may be a normal condition.
time, the machine shuts down.
See the Idle Shut Down Timer.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-8
F-8
TROUBLESHOOTING & REPAIR
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
detailed in the beginning of this manual.
PROBLEMS
POSSIBLE AREAS OF
RECOMMENDED
(SYMPTOMS)
MISADJUSTMENT(S)
COURSE OF ACTION
FUNCTION PROBLEMS
The output control potentiometer 1. The output control switch (SW3) 1. The output control potentiome-
does not function when the output
control switch (SW3) is in the
“Local” position. The DC-655
operates normally when controlled
remotely.
may be defective.
ter or associated wiring may be
faulty. See the Wiring Diagram.
The remote output control unit 1. The remote control unit or con- 1. The output control switch (SW3)
does not function properly when
the output control switch (SW3) is
in the “Remote” position. The DC-
655 operates normally when con-
trolled locally from the machine’s
output control potentiometer.
necting cable may be defective.
Check or replace.
may be defective. Check or
replace.
Diagram.
See the Wiring
2. Check the remote control leads
#75, #76 and #77 at plug P15,
the terminal strip and the 14-pin
MS type connector. Check for
loose or faulty connections.
See the Wiring Diagram.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-9
F-9
TROUBLESHOOTING & REPAIR
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
detailed in the beginning of this manual.
PROBLEMS
POSSIBLE AREAS OF
RECOMMENDED
(SYMPTOMS)
MISADJUSTMENT(S)
COURSE OF ACTION
FUNCTION PROBLEMS
The Thermal Protection Light is on 1. Check for obstructions that 1. The fan motor could be faulty.
but the fan does not run.
could prevent the fan from turn-
ing.
Check or replace.
2. The Thermal Fan/Snubber PC
Board may be defective. See
the Thermal Fan/Snubber PC
Board LED Chart.
The fan runs continuously.
1. Note: The fan is thermal con- 1. The Thermal Fan Thermistor
trolled. Under normal condi-
tions, it does not continuously
run.
may be faulty. See the Wiring
Diagram.
2. The Thermal Fan/Snubber PC
Board may be defective. See
the Thermal Fan/Snubber PC
Board LED Chart.
One or both of the optional digital 1. Check for loose plugs P13 and 1. The digital meter board may not
meters are not lit.
P12 at the digital meter PC
board.
be receiving voltages from the
T1 transformer windings.
Perform the Main Transformer
Test.
2. Check the wiring between Plug
J13 and the associated leads at
the main transformer. See the
Wiring Diagram.
3. The digital meter PC board may
be faulty.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-10
F-10
TROUBLESHOOTING & REPAIR
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
detailed in the beginning of this manual.
PROBLEMS
POSSIBLE AREAS OF
RECOMMENDED
(SYMPTOMS)
MISADJUSTMENT(S)
COURSE OF ACTION
FUNCTION PROBLEMS
The optional digital meter is not 1. Make certain plugs P12 and 1. Check feedback leads #222,
working properly and/or the dis-
play is erratic.
P13 are securely plugged into
the digital meter PC board.
Also make sure plug P3 is
securely plugged into the con-
trol board.
#210, #201 and #202 for loose
or faulty connections. See the
Wiring Diagram.
2. The optional digital meter PC
board may be faulty.
The analog meters are not reading 1. Make sure plug P3 is securely 1. Check feedback leads #222,
correctly.
plugged into the control board
and plug J14 is securely seated
in the plug assembly from the
control board.
#210, #201 and #202 for loose
or faulty connections. See the
Wiring Diagram.
2. The meter(s) may be defective.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-11
F-11
TROUBLESHOOTING & REPAIR
Observe Safety Guidelines
detailed in the beginning of this manual.
TROUBLESHOOTING GUIDE
PROBLEMS
POSSIBLE AREAS OF
RECOMMENDED
(SYMPTOMS)
MISADJUSTMENT(S)
COURSE OF ACTION
WELDING PROBLEMS
Poor arc characteristics in all 1. Check the three-phase input 1. Check the weld mode switch
processes.
line voltage at the machine.
The input voltage must match
the rating plate and reconnect
panel.
(SW2) and associated leads for
proper operation or loose or
faulty connections. See the
Wiring Diagram.
2. Check the welding cables for 2. Perform the Firing Board Test.
loose or faulty connections.
3. Perform the SCR Bridge Test.
3. Make sure the proper welding
4. Perform the Main Transformer
procedures are being used.
Test.
(Wire feed speed, arc voltage
and wire size)
5. The control board may be
faulty. See the Control Board
LED Chart.
4. Make sure the negative welding
cable is connected to the cor-
rect negative output terminal.
(Low or High inductance)
Poor arc striking with semiauto- 1. Make sure the proper welding 1. Perform the Firing Board Test.
matic or automatic wire feeders.
procedures are being used.
(Wire feed speed, arc voltage
and wire size)
2. Perform the SCR Bridge Test.
3. The control board may be
faulty. See the Control Board
LED Chart.
2. Check the welding cables for
loose or faulty connections.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-12
F-12
TROUBLESHOOTING & REPAIR
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
detailed in the beginning of this manual.
PROBLEMS
POSSIBLE AREAS OF
RECOMMENDED
(SYMPTOMS)
MISADJUSTMENT(S)
COURSE OF ACTION
WELDING PROBLEMS
The arc is variable or sluggish.
1. Check the three-phase input 1. Check the weld mode switch
line voltage at the machine.
The input voltage must match
the rating plate and reconnect
panel configuration.
(SW2) and associated leads for
proper operation or loose or
faulty connections. See the
Wiring Diagram.
2. Make sure the machine’s set- 2. Perform the Firing Board Test.
tings are correct for the welding
3. Perform the SCR Bridge Test.
process.
4. Perform the Main Transformer
3. Check the welding cables for
Test.
loose or faulty connections.
Also make sure cables are sized 5. The control board may be
correctly for the welding cur-
rent.
faulty. See the Control Board
LED Chart.
4. See CV Mode Current
Limiting.
The Arc Force Control (R4) has no 1. The Arc Force Control is active 1. Check the Arc Force Control
effect on the arc.
only in the CC Stick mode.
potentiometer (R4) for the cor-
rect resistance and proper
operation. Normal resistance is
10,000 ohms.
2. The effect of the Arc Force
Control will be less noticeable
at high welding currents. Weld
at low currents (less than 150 2. Check the continuity of leads
amps) and check the Arc Force
control function.
#321, #322 and #328 from the
Arc Force Control to the control
board. See the Wiring Diagram.
3. The control board may be
faulty. Replace.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-800-833-9353.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-13
F-13
TROUBLESHOOTING & REPAIR
INTERNAL TRIGGER CIRCUIT TEST
WARNING
Service and repair should be performed by only Lincoln Electric factory trained person-
nel. Unauthorized repairs performed on this equipment may result in danger to the tech-
nician or machine operator and will invalidate your factory warranty. For your safety and
to avoid electrical shock, please observe all safety notes and precautions detailed
throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353
(WELD).
TEST DESCRIPTION
This test will help determine if the wiring and connections are good from the 14-pin
receptacle and terminal strip through the P15 and P16 connectors and thermostats to the
firing board. The technician will also be able to determine if the 42 VAC trigger supply
voltage is present.
MATERIALS NEEDED
Ohmmeter (Multimeter)
DC-655 Wiring Diagram
Simplified Trigger Diagram
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-14
F-14
TROUBLESHOOTING & REPAIR
INTERNAL TRIGGER CIRCUIT TEST (continued)
FIGURE F.1 – FIRING BOARD TRIGGER CIRCUIT TEST POINTS AND LEDS
LED7
LED8
LED9
J5
8
7
6
5
4
3
2
1
16
15
14
13
12
11
10
9
LED2
LED1
G2699-[ ]
J6
LED10
LED4
LED6
LED3
LED5
J7
J4
FIRING BOARD
2. If LED 10 does not light when the trigger cir-
cuit is activated, proceed with the following
voltage and continuity checks.
WARNING
ELECTRIC SHOCK can kill.
3. Check the 10 Amp circuit breaker. It is the
one closest to the 115V duplex receptacle.
Reset if tripped.
• Do not touch electrically hot
parts.
TEST PROCEDURE
1. With the correct input power applied to the
DC-655 and the trigger circuit activated,
LED 10 on the firing board should be lit.
See Figure F.1. If LED 10 lights when the
trigger is activated, the wiring and circuitry
to the firing board is good. Perform the
Firing Board Test and see the Control
Board LED Chart. See the Simplified
Trigger Diagram.
NOTE: LED 10 should not be lit if the trigger
circuit is not activated.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-15
F-15
TROUBLESHOOTING & REPAIR
FIGURE F.2 – TERMINAL STRIP AND 14-PIN RECEPTACLE
K=42
J=31
A=32
14 PIN MS RECEPTACLE
B=GND
L
I=41
N
C=2
H=21
G=75
D=4
E=77
F=76
M
POSITIVE
OUTPUT
TERMINAL
LOW INDUCTANCE
HIGH INDUCTANCE
NEGATIVE OUTPUT
NEGATIVE OUTPUT
TERMINAL
TERMINAL STRIP
COVER PANEL
TERMINAL
+21 -21 41
4
2
31 32
75 76 77
TERMINAL STRIP
4. Check for the presence of 42 VAC at the ter-
minal strip ( #2 to #41). See the Simplified
Trigger Diagram.
8. Check continuity (zero ohms) from pin “D”
(lead #4) at the 14-pin receptacle to the out-
put terminal switch and also to plug J5-pin
9 at the firing board. See the Simplified
Trigger Diagram and Figures F.1 and F.2. If
a resistance of any value is indicated, check
the associated wires and plugs.
5. If 42 VAC is not present at the terminal strip,
check the circuit breaker and leads #42A
and #41 at the P15 connector. See the
Simplified Trigger Diagram. Also perform
the Main Transformer Test.
6. Remove the main input supply power to the
DC-655 machine.
7. Check continuity (zero ohms) from lead
#42A ( plug P15 pin-13) to lead #2 at the 14-
pin receptacle pin “C”. Also check continu-
ity to the output terminal switch. See the
Simplified Trigger Diagram. If a resistance
of any value is indicated, check the associ-
ated wires and plugs.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-16
F-16
TROUBLESHOOTING & REPAIR
9. Check continuity (zero ohms) from lead #41
(plug P15 pin-10) to plug J5-pin 1 at the fir-
ing board. See the Simplified Trigger
Diagram and Figure F.1. If a resistance of
any value is indicated, check the associat-
ed wires, plugs and thermostats.
FIGURE F.3 – SIMPLIFIED TRIGGER DIAGRAM
10AMP
CIRCUIT
BREAKER
TO #42 AT MAIN
TRANSFORMER
42A
FIRING BOARD
TERMINAL
STRIP
P15
13
P16
11J5
10J5
#309
14-PIN
RECEPTACLE
TO
CONTROL
BOARD
OUTPUT
TERMINAL
SWITCH
C
2
4
2
5
2
#
5
6
LED10
#310
LATCHING
RESISTOR
ENABLE
D
4
9
#4
#4
9J5
1J5
11
10
#41
41
#273
#41
FIRING
CIRCUIT
ENABLE
N.C.
CHOKE LEAD
THERMOSTAT
N.C.
SECONDARY
THERMOSTAT
TO #41 AT MAIN
TRANSFORMER
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-17
F-17
TROUBLESHOOTING & REPAIR
FIRING BOARD TEST
WARNING
Service and repair should be performed by only Lincoln Electric factory trained person-
nel. Unauthorized repairs performed on this equipment may result in danger to the tech-
nician or machine operator and will invalidate your factory warranty. For your safety and
to avoid electrical shock, please observe all safety notes and precautions detailed
throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353
(WELD).
TEST DESCRIPTION
This test will help determine whether or not the firing board is receiving the correct volt-
ages and signals. The LEDs (Light Emitting Diodes) will help determine if the firing board
is generating gate signals for the main SCRs.
MATERIALS NEEDED
Volt/ohmmeter (Multimeter)
DC-655 wiring diagram and firing board schematic drawing
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-18
F-18
TROUBLESHOOTING & REPAIR
FIRING BOARD TEST (continued)
FIGURE F.4 – FIRING BOARD TRIGGER CIRCUIT TEST POINTS AND LEDs
LED7
LED8
LED9
J5
(205) 8
16 (204)
15 (203)
14
(206) 7
(207) 6
(208) 5
13 (231)
12 (215)
11
4
3
2
1
LED2
LED1
G2699-[ ]
10
9
J6
J7
LED10
LED4
LED6
LED3
LED5
J4
FIRING BOARD
TEST PROCEDURE
1. Disconnect the AC input power to the DC-
655 machine.
WARNING
ELECTRIC SHOCK can kill.
2. Locate the firing board on the left side of
the control box.
• Do not touch electrically hot
parts.
3. Perform a visual inspection on the firing
board to see if there are any loose or faulty
connections or physical damage.
4. Connect the correct AC input power to the
DC-655.
5. Turn the power switch (SW1) to the ON
position.
6. LEDs 7, 8 and 9 should be lit and equally
bright. See Figure F.4 to locate the LEDs.
Use Table F.1 to check operation of LEDs 7,
8, and 9. The three LEDs should be of
equal intensity.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-19
F-19
TROUBLESHOOTING & REPAIR
FIRING BOARD TEST (continued)
TABLE F.1 - LED 7, 8, 9 AND 10
IF
THEN
LED 7 is ON
32 VAC power is being supplied to the
firing board from leads #203 and
#204 connected to the phase angle
winding in the Main Transformer.
Normal is 32 VAC.
LED 7 is not lit or is dimmer than
the other LEDs
The proper AC voltage may not be
reaching the firing board. Check for
loose or faulty connections. Perform
the Main Transformer Test.
LED 8 is ON
32 VAC power is being supplied to the
firing board from leads #205 and #206
connected to the phase angle winding in
the Main Transformer.
LED 8 is not lit or is dimmer than
the other LEDs
The proper AC power may not be
reaching the firing board. Check for
loose or faulty connections. Perform
the Main Transformer Test.
LED 9 is ON
32 VAC power is being supplied to
the firing board from leads #207 and
#208 connected to the phase angle
winding in the Main Transformer.
LED 9 is not lit or is dimmer than
the other LEDs
The proper AC power may not be
reaching the firing board. Check for
loose or faulty connections. Perform
the Main Transformer Test.
LED 10 is ON
This indicates the trigger circuit is
activated at the 14-pin receptacle or
the terminal strip or that the Output
Terminal Switch (SW5) is closed.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-20
F-20
TROUBLESHOOTING & REPAIR
FIGURE F.5 – 14-PIN RECEPTACLE
K=42
J=31
A=32
B=GND
I=41
L
N
C=2
H=21
G=75
D=4
E=77
F=76
M
7. Connect a jumper wire from pin C (lead #2)
to pin D (lead #4) at the 14-pin receptacle.
See Figure F.5. (Or put the Output Terminal
Switch in the ON position.) This should ini-
tiate machine output at the welding termi-
nals. LED 10 on the firing board should
now be on. See Table F.1. If LED 10 does
not glow when leads #2 and #4 are con-
nected together, perform the Internal
Trigger Test. The firing board may be
faulty.
11. Rotate the Output Control Potentiometer
(R1). As the pot is turned clockwise, LEDs
1 through 6 should get brighter. As the pot
is turned counter-clockwise, the LEDs
should get dimmer.
If the LEDs glow and change in brightness
equally as the pot is turned, and the prob-
lem continues, the SCR bridge may be
faulty. Perform the SCR Output Bridge
Test.
If one or two lights stay bright or dim and
the others change, this could indicate an
open or shorted gate lead or faulty snubber
board. Perform the SCR Output Bridge
Test. If the Output Bridge and associated
gate leads are OK, the firing board may be
faulty.
8. Locate LEDs 1 to 6 on the firing board. See
Figure F.4. Each LED should glow with
equal brightness.
NOTE: LEDs 1 through 6 indicate that the
SCR gate firing signals are being generated
by the firing board.
9. Set the Output Control Switch (SW3) in the
“Output Control at DC-655” (local) position.
If all of LEDs 1 through 6 do not glow or do
not change in brightness equally as the
output control is rotated, go to step 12.
10. Set the Mode Switch (SW2) in a constant
voltage (CV) position.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-21
F-21
TROUBLESHOOTING & REPAIR
12. Test for 9.5 VDC to 11.0 VDC between
leads #231 and #215 on the firing board.
13. Test for approximately 5.5 VDC between
leads #231 and #215 on the firing board.
See Figure F.4.
Make sure the Mode Switch (SW2) is in a
constant voltage (CV) position.
Put the Mode Switch (SW2) in the constant
current (CC) position.
Locate plug J5 on the firing board. Locate
leads #231 (pin-13) and #215 (pin-12). See
Figure F.4.
Rotate the Output Control (R1) clockwise
and counter-clockwise. The DC voltage
between leads #231 and #215 should be
constant at approximately 5.5 VDC. This
voltage should not vary when the output
control is turned.
Connect a jumper wire from pin C (lead #2)
to pin D (lead #4) at the 14-pin receptacle.
(Or put the Output Terminal Switch in the
ON position.) This should initiate machine
output at the welding terminals.
Rotate the Output Control (R1) clockwise
and counter-clockwise. The DC voltage
between leads #231 and #215 should vary
from 9.5 VDC to 11.0 VDC as the control is
turned from minimum to maximum. If the
voltage varies and LEDs 1 through 6 do
NOT vary in brightness, the firing board
may be faulty.
If the voltage does NOT vary, the control
board, control potentiometer or associated
leads may be faulty. See the Wiring
Diagram.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-22
F-22
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER (T1) VOLTAGE TEST
WARNING
Service and repair should be performed by only Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manu-
al.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).
TEST DESCRIPTION
This test will determine if the correct voltages are being applied to the primary windings of
the main transformer. The secondary windings, the auxiliary windings and the phase angle
windings will also be checked.
MATERIALS NEEDED
Volt/ohmmeter (Multimeter)
DC-655 Wiring Diagram
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-23
F-23
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER (T1) VOLTAGE TEST (continued)
FIGURE F.6 – INPUT CONTACTOR AND PRIMARY LEADS
TEST PROCEDURE
1. Disconnect the main input power from the
DC-655.
6. Make sure the input contactor (CR1) ener-
gizes.
2. Inspect the input contactor, reconnect
panel and primary leads to the main trans-
former for loose or faulty connections. See
Figure F.6. Remove the case sides.
7. Test with an AC voltmeter for the proper
main AC input voltages applied to the line
side of the input contactor (CR1). See the
Wiring Diagram. If the correct voltages are
not present at the line side of the input
contactor, check the input fuses and leads.
3. Confirm that the reconnect panel is config-
ured correctly for the three-phase AC input
power supplied to the DC-655. See the
connection diagram located on the inside
of the input box assembly.
a. L1 to L2
b. L2 to L3
c. L1 to L3
4. Connect the correct AC three-phase input
power to the DC-655 machine.
8. Test with an AC voltmeter for the proper
AC input voltages at the output side of the
input contactor (CR1). See the Wiring
Diagram. If the correct voltages are not
present, perform the Input Contactor
Test.
WARNING
ELECTRIC SHOCK can kill.
• Do not touch electrically hot
parts.
a. T1 to T2
b. T2 to T3
c. T1 to T3
5. Turn the power switch (SW1) to the ON
position.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-24
F-24
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER (T1) VOLTAGE TEST (continued)
FIGURE F.7 - MAIN TRANSFORMER SECONDARY LEADS TO
COMMON BUS VOLTAGE CHECK
COMMON
BUS
CHOKE
SECONDARY
LEADS (6)
MAIN
TRANSFORMER
9. Test with an AC voltmeter for approximately
NOTE: The secondary voltages will vary if the
input line voltages vary. If any one or more of the
voltage checks are incorrect, check for loose or
faulty connections. See the Wiring Diagram. If
the leads and connections are OK, the main
transformer may be faulty.
55 VAC from each of the six main trans-
former secondary leads to the common bus
connected to the output choke. See Figure
F.7.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-25
F-25
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER (T1) VOLTAGE TEST (continued)
FIGURE F.8 - TERMINAL STRIP
14 PIN MS RECEPTACLE
POSITIVE
OUTPUT
TERMINAL
HIGH INDUCTANCE
NEGATIVE OUTPUT
TERMINAL
LOW INDUCTANCE
NEGATIVE OUTPUT
TERMINAL
TERMINAL STRIP
COVER PANEL
+21 -21 41
4
2
31 32
75 76 77
TERMINAL STRIP
10. Test for 115 VAC between leads #31 and
#32 on the terminal strip. The terminal strip
can be accessed by removing the small
panel at the lower portion of the case front.
See Figure F.8. 115 VAC AC should also be
present at the 115 VAC receptacle. If the
correct voltage is not present, make sure
the 20 amp circuit breaker is not tripped or
faulty. Also check the wiring between the
main transformer, the terminal strip, the cir-
cuit breaker and the receptacle. See the
Wiring Diagram.
12. Test for 42 VAC between leads #41 and #2
on the terminal strip. The terminal strip can
be accessed by removing the small panel
at the lower portion of the case front. See
Figure F.8. If the correct voltage is not pre-
sent, make sure the 10 amp circuit breaker
is not tripped or faulty. Also check the
wiring between the main transformer, the
terminal strip, and the circuit breaker. See
the Wiring Diagram.
13. Remove the AC input power to the DC-
655. Remove the screws from the control
box cover and carefully lower the cover.
11. If 115 VAC is NOT present and the wiring
and circuit breaker are good, the main
transformer may be defective.
14. Locate the firing board on the left side of
the control box.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-26
F-26
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER (T1) VOLTAGE TEST (continued)
FIGURE F.9 - FIRING BOARD PLUG J5 PINS
LED7
LED8
LED9
J5
(205) 8
16 (204)
15 (203)
14
(206) 7
(207) 6
(208) 5
13 (231)
12 (215)
11
4
3
2
1
LED2
LED1
G2699-[ ]
10
9
J6
J7
LED10
LED4
LED6
LED3
LED5
J4
FIRING BOARD
15. Locate plug J5 on the firing board. See
Figure F.9.
17. Locate plug J13 on the optional digital
meter board. If a digital meter board is not
in place, plug J13 will not be used but will
be present in the harness. Check the fol-
lowing voltages at the appropriate leads
and pin locations.
WARNING
ELECTRIC SHOCK can kill.
10 VAC Plug J13 pin-1 (lead #331) to pin-2
(lead #332)
• Do not touch electrically hot
parts.
10 VAC Plug J13 pin-4 (lead #333) to pin-5
(lead #334)
42 VAC Plug J13 pin-3 (lead #335) to pin-6
(lead #336)
18. If the correct primary voltages are applied
to the main transformer and any of the sec-
ondary voltages are missing or not correct,
the transformer may be faulty.
16. Turn on the DC-655 and check for approx-
imately 32 VAC at the following leads and
pins at plug J5. These are the phase angle
winding voltages. See Fig. F.9.
NOTE: Always check the wiring between
the transformer windings and the test
points before replacing the transformer.
Plug J5 pin-15 (lead #203) to pin-16 (lead
#204)
Plug J5 pin-8 (lead #205) to pin-7 (lead
#206)
Plug J5 pin-6 (lead #207) to pin-5 (lead
#208)
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-27
F-27
TROUBLESHOOTING & REPAIR
CONTROL TRANSFORMER (T2) TEST
WARNING
Service and repair should be performed by only Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manu-
al.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).
TEST DESCRIPTION
This procedure will determine if the correct voltage is being applied to the primary of the con-
trol transformer and also if the correct voltage is being induced upon the secondary winding.
MATERIALS NEEDED
Volt/ohmmeter (Multimeter)
DC-655 Wiring Diagram
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-28
F-28
TROUBLESHOOTING & REPAIR
CONTROL TRANSFORMER (T2) TEST (continued)
FIGURE F.10 – CONTROL TRANSFORMER
211
TEST PROCEDURE
1. Disconnect the main AC input voltage to the
4. Locate the control transformer primary leads
(H1, H2, H3, etc.). See the Wiring Diagram.
DC-655.
2. Remove the case top and sides.
NOTE: Unused leads should be insulated and
taped. Inspect for broken or incorrect connec-
tions.
3. Locate the control transformer (T2) on the
left side of the input box (facing the back of
the machine). See Figure F.10.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-29
F-29
TROUBLESHOOTING & REPAIR
CONTROL TRANSFORMER (T2) TEST (continued)
5. Locate the control transformer secondary
leads. See Figure F.10. Lead X1 is con-
nected to the coil terminal on the CR1 input
contactor. Lead X2 is spliced into lead
#211, which is then connected to the input
power switch (SW1).
7. If approximately 115 VAC is present at leads
X1 to X2, the control transformer is function-
ing properly.
8. If approximately 115 VAC is NOT present at
leads X1 to X2, make certain the correct
input voltage is being applied to the primary
winding of the control transformer and that
the correct primary leads (H1, H2, H3, etc.)
are being used. See the connection infor-
mation diagram on the input access door.
WARNING
HIGH VOLTAGE is present at
the input leads.
9. If the correct voltage is being applied to the
primary of the control transformer and the
secondary voltage is incorrect or not pre-
sent, the control transformer may be defec-
tive.
6. Apply the correct three-phase input power
to the DC-655 and check for 115 VAC at
leads X1 to X2.
NOTE: The DC-655 does not have to be ON
to perform this test. If the main AC input
supply voltage varies, the control trans-
former secondary voltage will vary by the
same percentage.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-30
F-30
TROUBLESHOOTING & REPAIR
CONTROL BOARD TRANSFORMER (T3) TEST
WARNING
Service and repair should be performed by only Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manu-
al.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).
TEST DESCRIPTION
This test will determine if the correct voltage is being applied to the primary winding of the
control board transformer (T3) and also if the correct voltage is being induced upon the sec-
ondary winding.
MATERIALS NEEDED
Volt/ohmmeter (Multimeter)
DC-655 Wiring Diagram
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-31
F-31
TROUBLESHOOTING & REPAIR
CONTROL BOARD TRANSFORMER (T3) TEST (continued)
FIGURE F.11 – CONTROL BOARD TRANSFORMER (T3) LEADS
CONTROL BOARD
TRANSFORMER
(T3)
CONTROL
BOX
SECONDARY
LEADS #281
AND #282
PRIMARY LEADS
AND #256
#255
TEST PROCEDURE
1. Disconnect the main AC input power to the
DC-655 machine.
5. Apply the correct three-phase input power
to the DC-655 and turn the power switch
(SW1) to the ON position.
2. Remove the case top and sides.
6. Carefully check for 42 VAC at the secondary
leads (#281 to #282). If 42 VAC is present,
the control board transformer (T3) is good. If
42 VAC is missing or low, proceed to the
next step.
3. Locate the control board transformer (T3)
mounted on the rear of the control box. See
Figure F.11.
4. Locate the transformer (T3) primary leads
(#255 and $256). See Figure F.11 and the
Wiring Diagram. Also locate the secondary
leads (#281 and #282).
7. Carefully check for 115 VAC at the primary
leads (#255 and #256). If the 115 VAC is
present but the secondary voltage (42 VAC)
is missing or low, the T3 transformer may be
faulty. Replace.
WARNING
8. If the 115 VAC is NOT present at the prima-
ry leads, check the associated switch (SW1)
and wiring. See the Wiring Diagram.
ELECTRIC SHOCK can kill.
• Do not touch electrically hot parts.
9. Perform the Control Transformer (T2) Test.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-32
F-32
TROUBLESHOOTING & REPAIR
INPUT CONTACTOR TEST
WARNING
Service and repair should be performed by only Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manu-
al.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).
TEST DESCRIPTION
This test will help determine if the input contactor is receiving the correct coil voltage and if
the contacts are functioning correctly.
MATERIALS NEEDED
Volt/ohmmeter (Multimeter)
3/8” Nut driver
DC-655 Wiring Diagram
External 120 VAC supply
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-33
F-33
TROUBLESHOOTING & REPAIR
INPUT CONTACTOR TEST (continued)
FIGURE F.12 – INPUT CONTACTOR CONNECTIONS
X1, #256
#255A
TEST PROCEDURE
1. Disconnect the main input supply power to
the machine.
5. Apply the correct three-phase input power
to the DC-655 and turn the power switch
(SW1) to the ON position.
2. With the 3/8” nut driver, remove the case top
and input access cover.
6. Check for 120 VAC at the contactor coil
leads.
3. Locate the three leads connected to the
input contactor coil (X1/#256 and #255A).
See Figure F.12.
7. If the 120 VAC is NOT present, with the input
power switch (SW1) on, check the switch
and associated circuitry. See the Wiring
Diagram. Also see the Control Board LED
Chart. Relay CR2 may be faulty. See the
Wiring Diagram. Perform the Control
Transformer (T2) Test.
4. Connect an AC voltmeter to the leads.
WARNING
ELECTRIC SHOCK can kill.
8. If the 120 VAC IS present and the contactor
does NOT activate, the input contactor is
faulty. Replace the input contactor.
• Do not touch electrically hot parts.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-34
F-34
TROUBLESHOOTING & REPAIR
INPUT CONTACTOR TEST (continued)
FIGURE F.13 – INPUT CONTACTOR TEST CONNECTIONS
X1, #256
#256
#255A
#255A
TEST FOR CONTACT CONTINUITY
1. Disconnect the main input supply power to
the DC-655 machine.
4. With the contactor activated, check the
continuity across the contacts. (Zero ohms
or very low resistance is normal.) See
Figure F.13. If the resistance is high, the
input contactor is faulty. Replace the input
contactor.
2. Locate, label and remove the three leads
connected to the input contactor coil
(X1/#256 and #255A). See Figure F.13.
5. When the contactor is NOT activated, the
resistance should be infinite or very high
across the contacts. If the resistance is
low, the input contactor is faulty. Replace
the input contactor.
WARNING
ELECTRIC SHOCK can kill.
• Do not touch electrically hot
parts.
3. Using the external 120 VAC supply, apply
120 VAC to the terminals of the input con-
tactor coil. If the contactor does NOT acti-
vate, the input contactor is faulty.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-35
F-35
TROUBLESHOOTING & REPAIR
STATIC SCR TEST
WARNING
Service and repair should be performed by only Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manu-
al.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).
TEST DESCRIPTION
The test is used to quickly determine if an SCR is shorted or “leaky.” See the Oscilloscope
Waveform Section in this manual for normal and abnormal SCR waveforms.
MATERIALS NEEDED
Analog ohmmeter (Multimeter)
DC-655 Wiring Diagram
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-36
F-36
TROUBLESHOOTING & REPAIR
STATIC SCR TEST (continued)
FIGURE F.14 – THERMAL FAN/SNUBBER BOARD AND FIRING BOARD PLUG LOCATIONS
THERMAL FAN / SNUBBER L10124-[ ]
LED2
LED6
LED5
LED1
LED4
LED3
PLUG J9
LED7
LED8
LED9
J5
LED2
LED1
G2699-[ ]
J6
LED10
LED4
LED6
LED3
LED5
J7
J4
FIRING BOARD
TEST PROCEDURE
1. Disconnect the main AC input power to the
DC-655 machine.
4. Test for high or infinite resistance from the
anode to the cathode of SCR1. See Figure
F.15. Use an analog ohmmeter (multimeter).
2. Locate and disconnect plug J9 from the
thermal fan/snubber board and plug J5 from
the firing board. See Figure F.14.
5. Test for high or infinite resistance from the
cathode to the anode of SCR1 by reversing
the meter leads. See Figure F.15.
3. Remove the red insulating paint from the
heat sink test points. See Figure F.15. DO
NOT DISASSEMBLE THE HEAT SINKS.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-37
F-37
TROUBLESHOOTING & REPAIR
STATIC SCR TEST (continued)
FIGURE F.15 – HEAT SINK TEST POINTS
ANODE
CATHODE
REMOVE
INSULATING
PAINT
6. If a high or infinite resistance is indicated for
both steps #4 and #5, SCR1 is not shorted.
8. Replace plug J9 into the thermal fan/snub-
ber board and plug J5 into the firing board.
7. If a low resistance is indicated in either steps
#4 or #5, there is a shorted SCR in the out-
put rectifier bridge. Repeat steps #4 and #5
for each of the six SCRs. It may be neces-
sary to disconnect the transformer sec-
ondary leads from the rectifier assembly to
isolate the defective SCR(s). See the Wiring
Diagram.
NOTE: To further check the SCRs’ functions use
an SCR tester and proceed to the Active SCR
Test.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-38
F-38
TROUBLESHOOTING & REPAIR
ACTIVE SCR TEST
WARNING
Service and repair should be performed by only Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manu-
al.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).
TEST DESCRIPTION
The Active SCR Test will determine if the device is able to be gated ON and conduct current
from anode to cathode.
MATERIALS NEEDED
An SCR Tester as specified in this procedure
DC-655 Wiring Diagram
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-39
F-39
TROUBLESHOOTING & REPAIR
ACTIVE SCR TEST (continued)
FIGURE F.16 – THERMAL FAN/SNUBBER BOARD AND FIRING BOARD PLUG LOCATIONS
THERMAL FAN / SNUBBER L10124-[ ]
LED2
LED6
LED5
LED1
LED4
LED3
PLUG J20
PLUG J9
LED7
LED8
LED9
J5
LED2
LED1
G2699-[ ]
J6
LED10
LED4
LED6
LED3
LED5
J7
J4
FIRING BOARD
TEST PROCEDURE
1. Disconnect the main AC input power to the
machine.
3. Remove the red insulating paint from the
heat sink test points. See Figure F.17. DO
NOT DISASSEMBLE THE HEAT SINKS.
2. Locate and disconnect plug J9 from the
thermal fan/snubber board and plug J5 from
the firing board. See Figure F.16.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-40
F-40
TROUBLESHOOTING & REPAIR
ACTIVE SCR TEST (continued)
FIGURE F.17 – HEAT SINK TEST POINTS
ANODE
CATHODE
SW1
R2
+
R1
V
SW2
A
R1 = 4 ohms/10 watts
R2 = 3 ohms/10 watts
6 VOLT
LANTERN
BATTERY
G
SCR
UNDER
TEST
C
To test SCRs construct the circuit outlined above. Resistor values are plus or minus
ten precent. The voltmeter scale should be low, approximately 0-5 or 0-10 volts DC.
4. Construct the circuit shown in Figure F.17.
One 6-volt lantern battery can be used. Set
the voltmeter scale low, at approximately 0-
5 volts or 0-10 volts.
b. If the voltage is 3-6 volts only when the
switch is closed or there is no voltage
when the switch is closed, the SCR is
defective.
a. Test the voltage level of the battery.
Short leads (A) and (C). Close switch
SW-1. Battery voltage should be 4.5
volts or higher. If lower, replace the bat-
tery.
NOTE: Be sure the battery is functioning
properly. A low battery can affect the
results of the test. Repeat the battery
test procedure in Step 4 if needed.
10. Open switch SW-1.
5. Connect the Tester to SCR 1 as shown in
Figure F.17.
11. Reconnect the Tester leads. See Figure
F.17.
a. Connect Tester lead (A) to the anode.
b. Connect Tester lead (C) to the cathode.
c. Connect Tester lead (G) to the gate.
a. Connect Tester lead (A) to the cathode.
b. Connect Tester lead (C) to the anode.
c. Disconnect Test lead (G) from the gate.
6. Close switch SW-1.
12. Close switch SW-1.
NOTE: Switch SW-2 should be open.
13. Read the meter for zero voltage.
a. If the voltage is zero, the SCR is func-
tioning.
7. Read the meter for zero voltage.
a. If the voltage reading is higher than zero,
the SCR is shorted.
b. If the voltage is higher than zero, the
SCR is shorted.
8. Close or keep closed switch SW-1.
9. Close switch SW-2 for 2 seconds and
release and read the meter.
14. Perform the Active Test Procedure outlined
in Steps 5-13 for SCRs 2-6.
a. If the voltage is 3-6 volts while the
switch is closed and after the switch is
open, the SCR is functioning.
15. Replace all SCR assemblies that do not
pass the above tests.
16. Plug J9 onto the thermal fan/snubber board
and plug J5 into the firing board.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-41
F-41
TROUBLESHOOTING & REPAIR
THERMAL FAN/SNUBBER BOARD LED CHART
LED #
LED FUNCTIONS AND INDICATIONS
(Machine is ON)
1
2
3
Indicates fan should be running.
Indicates welding current is greater than 200 amps.
Indicates fan should be running due to heating of main
SCRs.
4
Indicates an open thermal fan thermistor or an open con-
nection between the thermistor and the thermal fan/snub-
ber board. See the Wiring Diagram (leads #319 and
#316).
5
6
Indicates a thermostat (choke or secondary) has opened.
The thermal protection light should also be illuminated.
Indicates the fan motor should be running. LED 6 should
be illuminated and the fan running when any
of the following LEDs are lit: LED 2, LED 3, LED 4, or
LED 5.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-42
F-42
TROUBLESHOOTING & REPAIR
CONTROL BOARD LED CHART
LED #
LED FUNCTIONS AND INDICATIONS
(Machine is ON)
1
Indicates that the mode switch (SW2) is in the CC mode.
When LED 1 is on, LED 6 should also be
illuminated.
2
3
Indicates that feedback voltage is present. This informa-
tion is used when the machine is in a CV mode. This LED
should get brighter as the output voltage is increased.
Indicates an input shutdown. The normally closed relay
CR2 will activate causing input contactor CR1 to open.
See Remote Control Leads Fault Protection
Shutdown, Shorted Rectifier Fault Protection and Idle
Shutdown Timer in the Operation Section.
4
Indicates an over current shutdown. See Over Current
Protection Shutdown in the Operation Section.
5
6
Indicates output current is present.
Indicates that the machine is in the CC mode. LED 6
should be on whenever LED 1 is lit.
7
8
Indicates that the +16 VDC power supply is functioning.
This circuitry is located on the control board.
Indicates the control signal is being generated to control
the firing of the output SCRs. This signal is sent to the
firing board. This LED should get dimmer as the output
voltage is increased. This LED will normally be off when
the machine is in the constant current mode at open
circuit.
9
Indicates that the -10 VDC power supply is functioning.
This circuitry is located on the control board.
10
11
Indicates that 42 VAC is being supplied to the control
board from the control board T3 transformer.
Indicates that feedback voltage is present. This informa-
tion is used when the machine is in the CC mode. This
LED should get brighter as the output voltage is
increased.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-43
F-43
TROUBLESHOOTING & REPAIR
NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM
CONSTANT CURRENT MODE – NO LOAD
0 volts
2 ms
50 volts
This is the typical DC open circuit
voltage waveform generated from a
properly operating machine. Note
that each vertical division represents
50 volts and that each horizontal divi-
sion represents 2 milliseconds in
time.
Note: Scope probes connected at
machine output terminals: (+) probe
to positive terminal, (-) probe to neg-
ative high inductance terminal.
SCOPE SETTINGS
Volts/Div.....................50V/Div.
Horizontal Sweep.....2 ms/Div.
Coupling ............................DC
Trigger .........................Internal
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-44
F-44
TROUBLESHOOTING & REPAIR
NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM
CONSTANT VOLTAGE MIG
MAXIMUM OUTPUT SETTING – NO LOAD
0 volts
2 ms
50 volts
This is the typical DC open circuit
voltage waveform generated from a
properly operating machine. Note
that each vertical division represents
50 volts and that each horizontal divi-
sion represents 2 milliseconds in
time.
Note: Scope probes connected at
machine output terminals: (+) probe
to positive terminal, (-) probe to neg-
ative high inductance terminal.
SCOPE SETTINGS
Volts/Div.....................50V/Div.
Horizontal Sweep.....2 ms/Div.
Coupling ............................DC
Trigger .........................Internal
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-45
F-45
TROUBLESHOOTING & REPAIR
NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM
CONSTANT VOLTAGE MIG
MINIMUM OUTPUT SETTING – NO LOAD
0 volts
2 ms
20 volts
This is the typical DC open circuit
voltage waveform generated from a
properly operating machine. Note
that each vertical division represents
20 volts and that each horizontal divi-
sion represents 2 milliseconds in
time.
Note: Scope probes connected at
machine output terminals: (+) probe
to positive terminal, (-) probe to neg-
ative high inductance terminal.
SCOPE SETTINGS
Volts/Div.....................20V/Div.
Horizontal Sweep.....2 ms/Div.
Coupling ............................DC
Trigger .........................Internal
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-46
F-46
TROUBLESHOOTING & REPAIR
TYPICAL OUTPUT VOLTAGE WAVEFORM - MACHINE LOADED
CONSTANT VOLTAGE MIG MODE
0 volts
20 volts
2 ms
This is the typical DC open circuit voltage wave-
form generated from a properly operating
machine. Note that each vertical division repre-
sents 20 volts and that each horizontal division
represents 2 milliseconds in time. The machine
was loaded with a resistance grid bank. The
grid bank meters read 650 amps at 44 VDC.
Note: Scope probes connected at machine out-
put terminals: (+) probe to positive terminal, (-)
probe to negative high inductance terminal.
SCOPE SETTINGS
Volts/Div.....................20V/Div.
Horizontal Sweep.....2 ms/Div.
Coupling ............................DC
Trigger .........................Internal
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-47
F-47
TROUBLESHOOTING & REPAIR
TYPICAL SCR GATE VOLTAGE WAVEFORM
CONSTANT VOLTAGE MIG
MAXIMUM OUTPUT SETTING – NO LOAD
0 volts
2 volts
5 ms
This is the typical DC open circuit voltage wave-
form. The machine was in an open circuit con-
dition (no load) and operating properly. Note
that each vertical division represents 2 volts and
that each horizontal division represents 5 milli-
seconds in time.
Note: Scope probes connected at SCR gate
and cathode: (+) probe to gate, (-) probe to
cathode.
SCOPE SETTINGS
Volts/Div.......................2V/Div.
Horizontal Sweep.....5 ms/Div.
Coupling ............................DC
Trigger .........................Internal
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-48
F-48
INSTALLATION
ABNORMAL OPEN CIRCUIT VOLTAGE WAVEFORM
CONSTANT VOLTAGE MIG
ONE OUTPUT SCR NOT FUNCTIONING
0 volts
20 volts
2 ms
This is NOT the typical DC open circuit voltage
waveform. One output SCR is not functioning.
Note the “gap” in the waveform. One SCR gate
is disconnected to simulate an open or non-
functioning output SCR. Each vertical division
represents 20 volts and each horizontal division
represents 2 milliseconds in time.
Note: Scope probes connected at machine out-
put terminals: (+) probe to positive terminal, (-)
probe to negative high inductance terminal.
SCOPE SETTINGS
Volts/Div.....................20V/Div.
Horizontal Sweep.....2 ms/Div.
Coupling ............................DC
Trigger .........................Internal
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-49
F-49
TROUBLESHOOTING & REPAIR
INPUT CONTACTOR (CR1) CLEANING/REPLACEMENT
WARNING
Service and repair should be performed by only Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manu-
al.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).
DESCRIPTION
The following procedure will aid the technician in inspecting, cleaning, and replacing the input
contactor.
MATERIALS NEEDED
Phillips head screw driver
5/16” Socket wrench
Flat head screw driver
Low pressure air source
Allen head type wrench
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-50
F-50
TROUBLESHOOTING & REPAIR
INPUT CONTACTOR (CR1) CLEANING/REPLACEMENT (continued)
FIGURE F.18 - INPUT CONTACTOR CLEANING AND REMOVAL
1. INPUT SUPPLY LINE
2. INPUT CONTACTOR CR1
3. RECONNECT PANEL
CLEANING PROCEDURE
CONTACTOR REPLACEMENT
PROCEDURE
1. Remove the main input supply power to the
machine.
1. Disconnect main input supply power to the
machine.
2. Locate and get access to the input contac-
tor (CR1) in the input box. See Figure F.18.
2. Locate and get access to the input contac-
tor (CR1) in the input box. See Figure F.18.
3. Remove the input contactor cover plate
using a phillips head screwdriver.
3. Disconnect the main input supply power
leads L1, L2, and L3 to the input contactor.
WARNING
Remove the control transformer primary
leads H1, H2 or H3 (dependent on input volt-
age) from the L1 and L3 terminals on the
input side of the contactor.
Do not apply input power to
the machine with the input
contactor cover plate re-
moved.
4. Disconnect the output leads T1, T2, and T3
from the input contactor.
5. Identify and label the leads connected to the
input contactor coil.
Diagram.
See the Wiring
4. Blow out any dirt or dust in or around the
contacts with a low pressure air stream.
6. Disconnect the leads from the input contac-
tor coil (leads X1, #256 and #255A). See the
Wiring Diagram.
5. Inspect the contacts for signs of excessive
wear, pitting, or contacts fused (stuck)
together.
7. Remove the three self-tapping mounting
screws using a 5/16” socket wrench.
a. If any of these conditions are present,
replace the input contactor assembly.
8. Remove the input contactor.
6. Replace the input contactor cover plate.
9. Insert the replacement input contactor and
install it following the procedures in reverse
order.
NOTE: Be sure to reconnect all leads cor-
rectly.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-51
F-51
TROUBLESHOOTING & REPAIR
SCR RECTIFIER BRIDGE REMOVAL AND
REPLACEMENT PROCEDURE
WARNING
Service and repair should be performed by only Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manu-
al.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).
DESCRIPTION
The following procedure will aid the technician in removing the SCR/Rectifier Bridge for main-
tenance or replacement.
MATERIALS NEEDED
1/2” Socket wrench
3/8” Wrench
1/2” Wrench
9/16” Wrench
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-52
F-52
TROUBLESHOOTING & REPAIR
SCR RECTIFIER BRIDGE REMOVAL AND
REPLACEMENT PROCEDURE (continued)
FIGURE F.19 - THERMAL FAN/SNUBBER BOARD PLUG LOCATIONS
THERMAL FAN / SNUBBER L10124-[ ]
LED2
LED6
LED5
LED1
LED4
LED3
PLUG J20
PLUG J9
PROCEDURE
1. Remove the input power to the DC-655
machine.
4. Disconnect lead #222 from the negative high
inductance output terminal. This lead runs
from plug J9 to the negative high inductance
output terminal. Cut any necessary cable
ties. See the Wiring Diagram.
2. Using the 3/8” wrench, remove the case top
and sides.
3. Locate and remove plugs J9 and J20 from
the Thermal Fan/Snubber Board. See Figure
F.19.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-53
F-53
TROUBLESHOOTING & REPAIR
SCR RECTIFIER BRIDGE REMOVAL AND
REPLACEMENT PROCEDURE (continued)
FIGURE F.20 – SCR RECTIFIER BRIDGE ASSEMBLY DETAILS
MAIN TRANSFORMER
SECONDARY LEADS
SCR
RECTIFIER
BRIDGE
LEG
ASSEMBLY
MOUNTING
BRACKETS
5. Using the 1/2” socket wrench, remove the
six transformer secondary leads from the
heat sink assembly. The small “A” leads do
not have to be removed. Note lead place-
ment for reassembly. See the Wiring
Diagram and Figure F.20.
REASSEMBLY
1. Upon reassembly, apply a thin coating of
Dow Corning 340 Heat Sink Compound to
all bolted connections.
2. With the left side horizontal mounting brack-
et removed, slide the heat sink assembly
into the machine.
6. With the 9/16” wrench, remove the shunt
from the left side of the heat sink assembly.
3. Support the heat sink assembly and install
the left side mounting bracket. Then mount
the heat sink assembly to the bracket with
four bolts. Note insulator placement.
7. With the 3/8” wrench, remove the four
mounting bolts that hold the heat sink
assembly to the horizontal mounting brack-
ets. Be sure to remove the insulators and
take note of placement for reassembly.
4. Attach the shunt to the left side of the heat
sink assembly.
8. While supporting the heat sink assembly,
remove the left side horizontal mounting
bracket from the left side leg assembly. See
Figure F.20.
5. Install the six transformer secondary leads
to the heat sink assembly. See the Wiring
Diagram.
9. Carefully slide the rectifier heat sink assem-
bly from the machine. Clear all leads.
6. Connect lead #222 to the high inductance
output terminal.
7. Install plugs J9 and J20 onto the thermal
fan/snubber board.
8. Replace any cable ties cut at disassembly.
9. Install the case top and sides.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-54
F-54
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER AND CHOKE REMOVAL
AND REPLACEMENT PROCEDURE
WARNING
Service and repair should be performed by only Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manu-
al.
If for any reason you do not understand the test procedures or are unable to perform the
test/repairs safely, contact the Lincoln Electric Service Department for electrical trou-
bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).
DESCRIPTION
The following procedure will aid the technician in removing the main transformer and choke
for maintenance or replacement.
MATERIALS NEEDED
3/8” Wrench
7/16” Wrench
9/16” Wrench
Wire cutters
Soldering iron and solder
1/2” Socket wrench
9/16” Socket wrench
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-55
F-55
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER AND CHOKE REMOVAL
AND REPLACEMENT PROCEDURE (continued)
FIGURE F.21 – OUTPUT CHOKE/MAIN TRANSFORMER ASSEMBLY DETAILS
CHOKE THERMOSTAT
(LEADS #273 AND 41A)
TOP LEAD (#222A)
CENTER TAP
(LOW INDUCTANCE
OUTPUT LEAD)
CHOKE / FRAME
MOUNTING
BOLTS (4)
ROPE SLING
BOTTOM CHOKE
LEAD (HIGH
INDUCTANCE
OUTPUT LEAD)
IRON/COIL
MOUNTING
BOLTS (4)
TRANSFORMER
SECONDARY
LEADS (6)
6. Using the 9/16” wrench, remove the high
inductance output lead from the bottom
choke lead. See Figure F.21.
PROCEDURE
1. Remove the input power to the DC-655
machine.
7. Support the choke with a crane or hoist.
2. Remove the case top and sides.
8. Using the 9/16” wrench, remove the four
bolts, washers and nuts mounting the choke
assembly to the transformer frame assem-
bly.
OUTPUT CHOKE REMOVAL
3. Label and remove leads #273 and 41A from
the choke thermostat.
9. Carefully lift the choke from the DC-655
machine.
4. Using the 9/16” wrench, remove the flexible
transformer secondary lead and the #222A
lead from the top lead of the output choke.
See Figure F.21.
5. Using the 9/16” wrench, remove the low
inductance output lead from the center tap
of the choke. See Figure F.21.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-56
F-56
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER AND CHOKE REMOVAL
AND REPLACEMENT PROCEDURE (continued)
MAIN TRANSFORMER REMOVAL
REASSEMBLY
10. With the 1/2” wrench, remove the six trans-
former secondary leads from the SCR heat
sink assembly.
1. Using the rope sling, carefully position the
iron/coil assembly onto the DC-655. Mount
it to the frame assembly with four bolts,
washers and nuts.
11. Remove the transformer primary leads from
the reconnect panel. Label for reassembly.
2. Attach the transformer primary leads to the
reconnect panel.
12. Carefully label and unsolder the following
leads from the transformer windings. Cut
any necessary cable ties. See the Wiring
Diagram.
3. Attach the six transformer secondary leads
to the SCR heat sink assembly.
4. Solder the following leads to the transformer
windings.
❒ 335
❒ 336
❒ 331
❒ 332
❒ 333
❒ 334
❒ 203
❒ 204
❒ 205
❒ 206
❒ 207
❒ 208
❒ 31
❒ 335
❒ 336
❒ 331
❒ 332
❒ 333
❒ 334
❒ 203
❒ 204
❒ 205
❒ 206
❒ 207
❒ 208
❒ 31
❒ 32A
❒ 41
❒ 32A
❒ 41
❒ 42A
❒ 41
❒ 42A
❒ 41
thermostat
thermostat
13. Using a rope sling and hoist, support the
iron/coil assembly. See Figure F.21.
5. Using a crane or hoist, carefully place the
choke onto the main transformer.
14. With the 9/16” wrench, remove the four
bolts, washers and nuts holding the iron/coil
assembly to the frame assembly.
6. Attach the high inductance output lead to
the bottom choke lead.
15. Cut or remove any necessary cable ties.
7. Attach the low inductance output lead to the
choke center tap.
16. Using the hoist, carefully remove the
iron/coil assembly from the DC-655
machine. Clear all leads.
8. Attach the #222A lead and flexible trans-
former secondary lead to the top choke
lead.
9. Attach leads #273 and 41A to the choke
thermostat.
10. Replace any cable ties cut at disassembly.
11. Install the case top and sides.
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
F-57
F-57
TROUBLESHOOTING & REPAIR
RETEST AFTER REPAIR
Should a machine under test be rejected for any reason requiring the removal of any mechanical part that could
affect the machine’s electrical characteristics, or if any electrical components are repaired or replaced, the machine
must be retested.
INPUT IDLE AMPS AND WATTS
Input volts/Phase/Hertz
208/3/60
Maximum Idle Amps
Maximum Idle KW
11.0
10.0
6.0
5.5
5.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
230/3/60
380/3/60
416/3/60
460/3/60
550/3/60
575/3/60
4.2.
4.0
200/3/50
220/3/50
230/3/50
380/3/50
400/3/50
415/3/50
440/3/50
500/3/50
550/3/50
21.0
19.1
18.3
11.0
10.5
10.1
9.6
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
8.4
7.7
MAXIMUM OPEN CIRCUIT VOLTAGES
Mode
Input Hertz
Open Circuit Volts
CC Stick
60
66/70
CV MIG
60
60
60
44/47
Auxiliary Output (#31-#32)
Auxiliary Output (#41-#42)
122/128 VAC
44/48 VAC
MINIMUM ACCEPTABLE OUTPUT VOLTAGE - AT MAXIMUM OUTPUT SETTINGS
Mode
CC Stick
Control Settings
Output Control at Maximum
Arc Force Control at
Minimum
Load
815 Amps @ 44.0 Volts (Min)
CV MIG
Output Control at Maximum
815 Amps @ 44.0 Volts (Min)
5 Amps @ 120/126 VAC (Min)
5 Amps #41/45 VAC (Min)
Auxiliary Output (#31-#32)
Auxiliary Output (#41-#42)
N/A
N/A
IDEALARC DC-655
Download from Www.Somanuals.com. All Manuals Search And Download.
SVM ERROR REPORTING FORM
We need to know if there are errors in our manuals. We also value any suggestions as to
additional tests or procedures that would make this SVM a better tool for you.
If you discover new or different “Problems or Symptoms” that are not covered in the three col-
umn troubleshooting chart, please share this information with us. Please include the
machine’s code number and how the problem was resolved.
Thank You,
Technical Services Group
Lincoln Electric Co.
22801 ST. Clair Ave.
Cleveland, Ohio 44117-1199
FAX 216-481-2309
SVM Number ___________________________
Page Number if necessary__________________
Your Company__________________________
Your Name_____________________________
Please give detailed description below:
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
SD287 01/99
Download from Www.Somanuals.com. All Manuals Search And Download.
G-1
G-1
ELECTRICAL DIAGRAMS
TABLE OF CONTENTS
ELECTRICAL DIAGRAMS SECTION
Electrical Diagrams Section...........................................................................................Section G
Wiring Diagram (60 Hz Domestic) (G3348-1)..............................................................................G-2
Control Board Schmatic (G3384) ................................................................................................G-3
Firing Board Schmatic (G2792)...................................................................................................G-4
Thermal Fan/Snubber P.C. Board Schematic (L10123)...............................................................G-5
Control Board Layout (G3385-1) .................................................................................................G-6
Firing Board Layout (G2699-2)....................................................................................................G-7
Thermal Fan/Snubber Board Layout (L10124-1).........................................................................G-8
DC 655
Download from Www.Somanuals.com. All Manuals Search And Download.
G-2
G-2
ELECTRICAL DIAGRAMS
Wiring Diagram (G3348-1)
P15
75
75
76
77
J15
75
75
76
77
10A 42V CIRCUIT BREAKER
8
7
6
5
4
3
2
1
1
2
DUAL (EXCEPT 380/500V
UNDER 346 VOLTS (SHOWN CONNECTED FOR LOW VOLTAGE)
&
230/400V)
&
SINGLE VOLTAGE
OUTPUT
J14
202
201
210
315
215
317
222
202
201
210
42A
42
1
2
3
CONTROL
AM
-
32
3
4
TO
SUPPLY
LINES
10K
R1
N.D.
H3
RECONNECT
PANEL
.0045MFD
3000V
236
237
75
R3
2
4
77
5
H2
4
5
6
7
8
3
2
1
-
VM
X1
6
2
2
C9
C8
C7
GND.
STUD
L3
L1
L2
TO
10K 1/4W
7
41
41
J16
RECONNECT
PANEL
OPTIONAL
ANALOG METERS
222
8
210
210
11
10
12
3
2
1
9
8
7
6
5
TO GROUND PER
NATIONAL
20A
W
V
32
32A
32A
31
76
75
21
41
42
9
115V
SW3
CIRCUIT
10
11
12
13
14
4
41
41
9
4
41
41
ELECTRICAL
CODE
31
N.E.
76
77
OUTPUT
CONTROL
SWITCH
238
226
OR
256
BREAKER
8
7
6
5
4
3
2
1
10
11
12
13
14
115V RECEPTACLE
4
U
202
201
210
315
215
317
222
336
334
333
335
332
331
6
5
4
3
2
CR
1
32A
222
32A
CONTACTOR
J12
J13
42A
222
42A
222
FLEX
LEAD
32
31
TO PRIMARY
COILS
2
CONNECT OR INSULATE
AS SHOWN ON INPUT
CONNECTION DIAGRAM
237
236
H1
255A
31
1
210
OPTIONAL DIGITAL
METER P.C. BOARD
T.S.2
SINGLE VOLTAGE OVER 345 VOLTS
TO
+21 -21 41
4
T.S.1
2
2
31 32
4
75 76 77
H4
H3
H2
H1
X2
N.D.
H2
RECONNECT
PANEL
SUPPLY
LINES
OPTIONS
H3
2
255
255
211
OUTPUT
TERMINAL
SWITCH
X1
L3
L1
L2
X1
SW1
POWER SWITCH
282
T2 CONTROL
TRANSFORMER
SW5
11
3
2
1
RED
281
TO GROUND PER
NATIONAL
ELECTRICAL
CODE
4
W
BLK
10
12
T3
V
CONTROL
256
255
BOARD
U
TRANSFORMER
CR
1
1
2
3
4
5
6
7
8
9
10
255
CONTACTOR
TO PRIMARY
COILS
201
202
75
1
1
2
3
PILOT
J3
H1
255A
W
256
LIGHT
2
3
4
256
4
5
6
7
8
5
J2
314
226
336
335
6
THERMAL
PROTECTION
231
210
281
J1
7
41
Y
305
BRASS
TERMINAL
LIGHT
8
317
+
-
9
N.J.
S1
9
41
10
282
238
318
310
309
315
222A
10
11
12
13
14
S
T1 MAIN
TRANSFORMER
42V
11
12
N.F.
F
SECONDARY
THERMOSTAT
1
2
3
4
41
41
CONTROL
P.C. BOARD
333
10V
OFF
S
273
41
41A
CHOKE LEAD
41A
41
301
F
1
2
3
J21
8
41
334
THERMOSTAT
42A
1
2
3
4
5
6
7
9
10 11 12 13 14 15 16
331
10V
S
F
2
3
G1
G2
G3
G4
G5
G6
1
4
5
6
7
8
1
2
5
32A
31
208
207
206
205
2
332
42A
S
F
3
4
5
6
J5
J4
J7
115V
S
PRI.
4
45V
41
6
9
4
31
31
F
310
309
215
231
10
11
12
13
14
15
N.A.
1
2
3
4
5
6
A
B
7
8
9
203
205
207
W
B
F
F
F
N.G.
FAN
MOTOR
1
2
3
32V
32V
32V
13
PRI.
10
14
15
12
214
203
204
261
262
263
B'
C
C'
S
S
S
341
204
AUX1
206
208
J22
261
32
11
P22
261
262
263
342
16
GREEN
4
5
6
7
8
1
1
7
8
2
4
77
2
3
4
262
263
342
2
A'
J6
3
215
FIRING CIRCUIT
P.C. BOARD
P16
300
4
SEC.
SEC.
42
32
31
9
31
76
75
21
41
42
GREEN
OUTPUT CHOKE
41
21
STANDARD
10
11
12
13
14
LOW
2
4
14-PIN
(-)
319
340
215
344
RECEPTACLE
(FRONT VIEW)
THERMAL FAN
THERMISTOR
HIGH
315
318
317
41
75
1
1
2
3
4
5
6
7
NTC
77
(-)
76
2
J11
222A
316
32A
300
G2
3
4
222
222
222
SW2
222
210
N.H.
J10
MODE
SWITCH
14
13
314
301
305
A4
TP3
222
(SHOWN IN CC
POSITION)
ARC FORCE
G1
G4
A5
12
11
10
10K
R4
322
320V
160J
8
30
A1
A3
A5
328
R2
(ALL 3)
300W
DUAL FEEDER P.C. BOARD
321
OPTIONS
C2 TP2
TP1
C6
G5
319
316
9
1
2
J20
A6
A3
A2
A1
G3
G6
222
C
.05MFD
8
1
210
J9
600V
7
255
1
2
3
4
2
3
214
261
(ALL 3)
G6
6
5
6
5
4
3
2
32
GREEN
2
4
77
262
SCR
3
SCR
SCR
1
NC
NO
COM
G3
G1
G5
G5
G4
G3
G2
G1
263
342
4
5
6
7
8
5
255A
OUTPUT SHUNT
(50 MV @800 AMPS)
4
C1
(+)
J8
3
CR
2
J23
2
1
+
-
J17
J19
J18
346
FOR OPTIONAL
1
42
PARALLELING KIT
32
77
31
9
31
76
75
21
41
42
THERMAL FAN/
SNUBBER P.C. BOARD
201 202
GREEN
OUTPUT
41
21
10
11
12
13
14
345
1
2
3
2
4
215
14-PIN
RECEPTACLE
(RIGHT)
32
GREEN
2
4
75
(FRONT VIEW)
4
5
6
7
8
76
G2
G4
G6
OUTPUT
RECTIFIER
ASSEMBLY
77
JUMPER
PLUG
TO J16
NOTES:
SCR
6
SCR
4
SCR
2
J6,J11
J20
1
J7,J10,J12,J14
1
J3
J4,J8,J13
31
76
75
21
41
42
9
N.A. LEADS
4
THRU
9
ARE NOT PRESENT ON 380/500V,
5
1
4
1
2
1
3
10
11
12
13
14
AND SINGLE VOLTAGES OVER 345V MACHINES.
1
2
3
A6
A2
A4
3
4
4
6
N.D. TAPE UP SEPARATELY TO PROVIDE AT LEAST
600V INSULATION.
8
5
6
10
2
32
GREEN
2
4
77
4
5
6
7
8
J1,J9,J15,J16
J17,J18,J19
J2
J5
N.E. PLUG
&
LEAD ASSEMBLY GOES TO EITHER J12 (OPTIONAL DIGITAL
METERS PC BD.) OR J14 (IN LINE CONNECTOR FOR ANALOG METERS).
1
6
1
7
1
8
42
N.F. LOCATED IN SECONDARY COIL WINDING.
32
77
31
9
31
76
75
21
41
42
7
12
14
16
8
9
GREEN
41
21
10
11
12
13
14
N.G. STANDARD 14-PIN RECEPTACLE PLUGS INTO J16 ON STANDARD
MACHINES AND IS REPLACED BY DUAL FEEDER OPTION IF USED.
2
4
14-PIN
CONNECTOR CAVITY NUMBERING SEQUENCE
(VIEWED FROM COMPONENT SIDE OF BOARD)
RECEPTACLE
(LEFT)
75
N.H. LOCATED ON OUTPUT RECTIFIER FLAT HEAT SINK.
(FRONT VIEW)
76
N.J. AS SHIPPED ONLY SWITCH #4 IS ON (UP). SEE INSTRUCTION MANUAL.
ELECTRICAL SYMBOLS PER E1537
11-6-98
G3348-1
I-UF
G3348-1
NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. The wiring diagram specific to your code is pasted inside one of the enclo-
sure panels of your machine.
DC 655
Download from Www.Somanuals.com. All Manuals Search And Download.
G-3
G-3
ELECTRICAL DIAGRAMS
Control Board Schematic (G3384)
POWER SUPPLY
IDLE SHUTDOWN
TIMER
TIMER OUTPUT
TIMER
CHIP
315
315
TIMER INPUT
SHORTED SCR
A.C. PROTECTION
TO
THERMAL FAN/
SNUBBER PCB
317
TO
THERMAL FAN/
SNUBBER PCB
TRIGGER
OPEN
318
317
ENABLE
TO (+)
OUTPUT STUD
Vco
CC
VFB
BUFFER
CONTROL
AMPLIFIER
GAIN=27
MODE
HOT START
SWITCHING
SLOPE
BUFFER
ARC FORCE
CC CONTROL
REFERENCE
FIRING
INTERCEPT
BUFFER
CV
INTERFACE
VFB
BUFFER
CURRENT SWITCH
0.5 SEC TIMER
>15 AMP
CURRENT
SWITCH
TO OPTIONAL
DIGITAL METER PCB
201
REF
COM
CURRENT FEED
BACK
CV SUBARC FEEDBACK
201
HOLD
LOW
SHUT-
DOWN
CURRENT
AMPLIFIER
202
202
TO OPTIONAL
DIGITAL METER PCB
CV FEEDBACK
CVI
START
OVER
CURRENT
PROTECTION
CV CURRENT LIMITING
REFERENCE
-10V
CONTROL POT
REFERENCE
PEAK
CURRENT
PROTECTION
IDLE ZERO
Ico
REFERENCE
REFERENCE
SIGNAL
POT FAULT
BUFFER
PROTECTION
TO
FIRING
PCB
A
G3384
G3384
A
NOTE: Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not avail-
able from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in
danger to the Machine Operator or Technician. Improper PC board repairs could result in damage to the machine.
DC 655
Download from Www.Somanuals.com. All Manuals Search And Download.
G-4
G-4
ELECTRICAL DIAGRAMS
Firing Board Schematic (G2792)
7-17-98A
G2792
G2792
7-17-98A
NOTE: Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not avail-
able from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in
DC 655
danger to the Machine Operator or Technician. Improper PC board repairs could result in damage to the machine.
Download from Www.Somanuals.com. All Manuals Search And Download.
G-5
G-5
ELECTRICAL DIAGRAMS
Thermal Fan/Snubber Board Schematic (L10123)
5-16-97A
L10123
L10123
5-16-97A
NOTE: Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not avail-
able from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in
SQUARE WAVE TIG 275
danger to the Machine Operator or Technician. Improper PC board repairs could result in damage to the machine.
Download from Www.Somanuals.com. All Manuals Search And Download.
G-6
G-6
ELECTRICAL DIAGRAMS
Control Board Layout (G3385-1)
CAPACITORS = MFD/VOLTS
RESISTORS = OHMS/1/4 WATT UNLESS OTHERWISE SPECIFIED
C-RW
G3385-1
DC 655
G3385-1
C-RW
Download from Www.Somanuals.com. All Manuals Search And Download.
G-7
G-7
ELECTRICAL DIAGRAMS
Firing Board Layout (G2699-2)
ITEM
REQ'D
PART NO.
DESCRIPTION
CAPACITORS
RESISTORS
=
MFD/VOLTS
7-17-98A
G2699-2
=
OHMS
DC 655
G2699-2
7-17-98A
Download from Www.Somanuals.com. All Manuals Search And Download.
G-8
G-8
ELECTRICAL DIAGRAMS
Thermal Fan/Snubber Board Layout (L10124-1)
8 . 7 5
4 . 5 0
. 2 5
9 . 0 0
0
0
. 2
J 9
J 8
J 2 0
J 1 0
J 1 1
R 3 1
R 3 0
R 2 9
R 2 8
C 2 3
O C I 1
C 2 6
R 1 3
R 1 2
D 3
C 1 7
O C I 2
T R I 1
L E D 3
R 2 4
R 2 5
R 2 6
X 2
Q 1
L E D 1
L E D 5
L E D 4
L E D 6
X 3
L E D 2
X 1
X 4
C 9
C 8
5
L 1 0 1 2 4 - 1
T H E R M A L F A N S N U B B E R
~ . 0 4
6
DC 655
L10124-1
5-16-97A
Download from Www.Somanuals.com. All Manuals Search And Download.
NOTES
DC 655
Download from Www.Somanuals.com. All Manuals Search And Download.
|