MONOCHROME MONITOR
SERVICE MANUAL
BEFORE SERVICING THE CHASSIS, READ
IN THIS MANUAL
MODEL:
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FEATURES
l
l
l
2000 display characters in a 8 x 8 dot format.
18 MHz bandwidth, medium class, composite signal input.
This monitor is compatible with a variety of home and personal computers
CONTROLS LOCATION
The
monochrome monitor uses a RCA jack connector.
The input signal is input through the RCA jack connector.
The input signal is based on the composite level.
Figure 2 shows the monitor controls on the front and rear panels.
I n d i c a t o r
H-Size
Video In
Contrast
Brightness Power
H-Position H-Hold V-Sue Power Cord
Figure 2, Monitor Controls
NOTE: Monitor cabinet not used on 6300T Models.
H-Hold
POWER (PUSH-ON)
Turn on the monitor by pressing the power switch.
The power indicator lights when the power is ON.
Always turn on the monitor before you turn on the
Turn this knob to stop horizontal rolling of the
picture.
computer.
H-Position
To turn the power OFF, just press this switch again.
Turn this knob clockwise to move the center of the
picture to the right; turn the knob counterclockwise
to move the center of the picture to the left.
Brightness
Turn this knob clockwise to increase brightness.
Contrast
Turn this knob
Turn this knob to adjust the horizontal size of the
picture.
to increase contrast.
Turn this knob to adjust the vertical size of the
picture.
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CIRCUIT DESCRIPTION
1. VIDEO AMPLIFIER
2. POWER SUPPLY
The Fig. 3 details the cascade video amplifier.
Video amplification is provided by the TR303 and
TR304. TR303 and TR304 are connected in a
The 120V AC line voltage is applied to the primary
of the
where it is stepped down through the
secondary winding to approximately 17V (AC).
After passing through the bridge rectifier circuit
cascade configuration. TR303 operates as
a
common emitter and TR304 operates in the
common base configuration. This minimized the
miller effect input capacitance and the difining
breakdown parameter for TR303 which becomes
BVCBO as opposed to BVCEO.
This enables selection of a higher speed/lower
breakdown transistor to be used in the video
amplifier.
and filter
the regulated DC supply voltage
is approximately 18V (DC). The 18V unregulated
B+ voltage is applied directly to the collector of the
B+ regulator
(R905,
control
operating level
variations occur, a correction voltage is produced
at the base of TR903 and is coupled directly to the
base of the error amplifier (TR902). This correction
A voltage divider network
R906) in which the B+ adjustment
is used to establish the desired
DC). When AC input voltage
The emitter of TR304 is driven by the collector of
TR303 which is
a
high frequency transistor.
Overall voltage gain for the stage is determined
by the ratio of R312 to R316. Bandwidth is within
3dB to 32 MHz.
voltage is then passed from the emitter of TR902
directly to the base of
and B+ voltage
regulation is then accomplished.
R316
1
l
l
TO
TR304
KTC2229
R314
TO
CRT CA
R317
330
TR303
TO
R309
75
R313
47
Figure 3,
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Frame
Vcc 2 Generator
Vertical
Oscillator
vcc 2
Generator
Oscillator
Vertical
o u t p u t
Power
Amplifier
Input
Frame-Synchro
Horizontal
output
Line Fly Back Phase
Horizontal
Oscillator
Input
Detector
Figure 4, BLOCK DIAGRAM OF THE TEA 2037A
3. COMPOSITE VIDEO INPUT AND HORIZONTAL/
VERTICAL DEFLECTION
3-l VIDEO INPUT (PIN 15)
3-3
LINE (H) OSCILLATOR (PIN 9)
The line oscillator is of the type which charges and
discharges a capacitor, since a perfectly linear
sawtooth wave form is not required.
The detection level for negative sync pulse at the
sync separation input (pin 15) is set at
the voltage at emitter of the Transistor (pin 15) is
When
The free running frequency is dependent on
R705 and VR702 and is governed by this expres-
above
lower than
the transistor is cut off. Voltage
enables the transistor to conduct
sion To = 085 x
oscillator free running frequency.
x
where To is the line
and the internal circuitry
synchronization function.
i s
enabled for
3-4 FRAME(V) OSCILLATOR (PIN 9)
Oscillator thresholds are internally fixed by
resistor
R603 are used to determine the
free-running frequency, the oscillator
free-running frequency is given by To
x R603.
0.15 x
3-2 COMPOSITE VIDEO INPUT (PIN 15)
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ADJUSTMENT
1. REGULATED B + ADJUSTMENT
5. HORIZONTAL POSITION
Connect high impedance voltmeter between
emitter and ground rotate the B
The horizontal position control (VH701) snould be
adjusted for the horizontal picture position.
adjustment control
12.0
to obtain a reading of
6. SUB-BRIGHT (VR703)
Adjust subbright control (VR703) for
of the raster when external brightness is turned to
cut off
2. FOCUS
Adjust the focus control (VR704) for best overall
focus of the test pattern (marked with the symbol
Usually the center and corners of the
screen do not focus at the same setting and a
compromise must be made.
maximum
7.
CENTERING
ADJUSTMENT
It the raster is not centered horizontally and verti-
cally it may be centered by removing the cabinet
back and adjusting the centering tabs on the neck
of the tube, located at the rear of the deflection
yoke. Turn the whole device clockwise or
counterclockwise. To increase the amount of raster
shift move the two tabs which project from the
device farther apart, if raster is tilted on an angle,
it may be straightened by loosening the deflection
yoke clamp and rotating the deflection yoke.
3. VERTICAL
The vertical size control (VR601) should be adjust
for the picture to fill the screen vertically.
4. HORIZONTAL SIZE
The horizontal size control (H-site coil) should be
adjusted for the picture to fill the screen horizontal-
ly.
BLOCK DIAGRAM
Input
Output
TR303, TR304
TR302
TEA
AC
,
R E G .
Filter
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SCHEMA1
CONTRAST
R602
OEFL
TEA2037
1
2
.
7
l N5392GP. 4
20.
6
A
VR702
I
2
NOTES: 1. RESISTORS ARE SHOWN IN OHMS
1.000
2. CAPACITORS ARE SHOWN
IN OTHERWISE NOTED P
3. All RESISTORS ARE
TOLERANCE UNLESS OTHERWISE NOTED
SAFETY NOTICE
K
THE
MARK OF
DIAGRAM
FEATURES IMPORTANT FOR PROTECTION FROM
ELECTRICAL SHOCK HAZARDS. WHEN SERVICING IT IS
ONLY MANUFACTURER’S SPECIFIED PARTS BE USED
1
IN
MARK OF THE SCHE
A
C
I
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DIAGRAM
3
9
/
-
VR703
EXT.
FBT
3 3 K
R 7 1 1
I
6 . Y
,
c 7 1 7
2
0
3
0 . 0 1
\
IMPORTANT AVIS SUR LA
MARQUE DE CE
SPECIAL
FIRE AND
LA
COMPREND
DES RAYONS
E N D E
P OUR
THAT
D A N G E R S
E T D E
CRITICAL
DE S
D E
S YMBO LE
DES
P AR LE HANUFACTURIER.
D
E
F
G
I
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TROUBLESHOOTING GUIDE
A N D P O W E R
REG CIRCUIT
7
YES
TROUBLE IN
N O
,
C H E C K C R T
V O L T A G E 4 5 0 V
2
C H E C K C R T ( H E A T E R ) V O L T A G E
L E A D
L E A D
YES
A B O V E
TROUBLE IN
T R 3 0 3 ,
C H E C K C R T
V O L T A G E
YES
(SUB-BRIGHT,,
B R I G H T , ,
(CONTRAST,,
V I D E O C A B L E
SYNC
TROUBLE
S Y N C T R O U B L E
TROUBLE IN
K T C
TR902,
KTC 1959
K T A
K T C
TR304
KTC 2229
B
U
K T D
T E A
2N 3904
TR303
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PRINTED CIRCUIT BOARD
1. MAIN PCB
ASSY PIN:
1
ASSY PIN:
GSEP-2112
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3. MAIN PCB (SOLDER SIDE)
4. LINE FILTER PCB (SOLDER SIDE)
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EXPLODED VIEW
REPLACEMENT PARTS LIST (MECHANICAL PARTS)
,
8
ASSY.
COVER
10
,
11
12
C R T BOARD
I
COVER,
303.928A COVER, PCB SHIELD CASE
13
*Outer Cabinet not used on 6300T Models.
F
E
D
I
C
I
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REPLACEMENT PARTS LIST
CAUTION: Components identified by the
have special characteristics important to safety.
Do not degrade the safety of the set through improper servicing.
symbols in the PARTS LIST and on the SCHEMATIC DIAGRAM
ABBREVIATIONS:
Capacitors . . . . CC: Ceramic (TC), CE: Chemical, CK: Ceramic (Hi-K),
BP: Bipolar, CQ: Mylar, PE: Polyester, PP: Polypropylene
Resistors
.
.
.
.
RD: Carbon Film, RS: Metal Oxide Film
(All CC and Capacitors are
50 Volts and all resistor,
unless otherwise noted).
Recommended Service Parts, R: Replacement Service
N O .
DESCRIPTION
REF. NO.
PART NO.
DESCRIPTION
R709
R710
RESISTOR
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD,
RD.
RD.
RD.
RD.
RD.
820 ohm
47K ohm
15K ohm
33K ohm
o h m
R301
Fi302
R303
R304
R305
R306
R307
R308
R309
R310
RD.
RD.
RD.
RD.
RD.
75 ohm
120K ohm
82K ohm
680 ohm
220 ohm
R712
R714
R715
R716
R717
R718
o h m
6 8K ohm
33K ohm
15K ohm
8K ohm
3 9 0 o h m
100 ohm
5 6 o h m
o h m
RD.
RD
RD.
RD.
RD
RD.
RD.
RD.
RD.
R720
R902
6 8k ohm
2 2K ohm
75K ohm
1 3K ohm
7 5 o h m
82 ohm
R312
R313
R314
A
R904
R905
R906
R907
VR301
VR601
RWR, 7W 18 ohm
S
47 ohm
RD.
390 ohm
560 ohm
560 ohm
2 4K ohm
3 3K ohm
RD.
RD.
R316
R317
R318
R319
R320
R321
R601
RD 2W 1 2K ohm
VARIABLE
S
S
S
S
S
S
S
S
RD.
RD.
RD.
RD
330 ohm
120 ohm
1 OK
SR 29R 2208
S R 2 9 R
SR 29R 4
VR702
VR703
VR704
VR705
100 ohm
4 7K ohm
33 ohm
S
R
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
RD.
3 3 MB
VARIABLE 250KB
1 5 ohm
560K ohm
2 2 ohm
18 ohm
S R
CAPACITOR
C E ,
2 2 0 8
R603
R605
R606
R607
R608
R609
R610
150K ohm
390K ohm
o h m
CE,
16V
CE, 22uF 16V
C E ,
2 2 ohm
1 OK ohm
82 ohm
A
CE.
1 6 V
C C ,
CE, 47uF
CE, 2 2 u F
CC,
R612
R613
R701
R702
R703
R704
6 8K ohm
150 ohm
150 ohm
560K ohm
50V
16V
CE,
CO. 0 22uF
C E .
S
S
3
ohm
47K ohm
3 3 K o h m
470 ohm
33 ohm
CE. 47uF 16V
R705
R706
R707
RD.
RD.
RD.
RD.
CO,
CE.
0
16V
CO, 0 22uF
C O ,
R708
6 8K ohm
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DESCRIPTION
REF. NO.
PART NO.
2
160V
16V
CE.
CO, 0
CE. 1
CO, 0
PP 0
CO, 0
0
25V
c
703
706
COIL
S
200V
20-0040
20-0039
PEAKING PL 4
PEAKING PL 3
CHOKE
C
CE, 4
PP. 0
CE,
25V
400V
COIL WIDTH
PEAKING PL
A
25V
16V
25V
20-0038
CE.
LINE
FILTER
A
S
BP. 4
CE,
MISCELLANEOUS
C 7 1 3
CE,
CRT,
(Green)
(Amber)
CK.
A
C715
C 7 1 6
c717
CRT,
A
A
A
1 l-0023
CC. 56pF 50V
CO, 0
T701
FBT
ASSY
CK. 0
CK, 0
0
50V
PCB MAIN
FUSE 0
1
50V
50V
50V
50V
A
07-0009
A
SWITCH, POWER
NEON LAMP
S P A R K G A P
CK, 0
CK, 0
CE,
N E 3 0 1
S G 3 0 1
25V
50V
VIDEO IN
S I G N A L
C A B L E
JACK, RCA PHONE
RCA TO RCA CABLE
CK, 0
CE, 47uF 16V
A
A
A
MPP. 0
CK, 0
CK, 0
125V
S O C K E T C R T
v2
WIRE ASSY SHIELD
125V
TRANS. POWER SHIELD
PWB LINE FILTER
I c.
AC POWER CORD
BOARD COMPL. W/TRAY
CONNECTOR ASSY FOR
CONNECTOR ASSY FOR LED
DIODE
.
.
D301
D601
PRINTED MATTERS
1
N4002
D 6 0 2
D 6 0 3
D 6 0 4
D701
1
1
KDSl555
ZENER
KIT,
PRINTING
A
A
OWNER’S MANUAL
PIN. STAPLE NO 10
B A G , P E
D 7 0 2
D 7 0 3
D 7 0 4
D 7 0 5
D706
1
1
1
RGPlOD
A
A
A
19-0048
1
1
0902
A D903
A
1
1
A D905
ZENER
LED (GREEN)
TRANSISTOR
KTC 1959-Y
TR301
T R 3 0 2
T R 3 0 3
TR304
TR601
19-0046
1
KTA562
TM-Y
1
A
TR701
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