Agilent Technologies Video Gaming Accessories 5962 8200 User Manual

Service Manual  
For Agilent Model  
6611C, 6612C, 6613C, 6614C  
System DC Power Supply  
For instruments with Serial Numbers:  
Agilent 6611C: US37450101 and up  
Agilent 6612C: US37460101 and up  
Agilent 6613C: US37460101 and up  
Agilent 6614C: US37460101 and up  
Agilent Part No. 5962-8200  
Microfiche No 5962-8201  
Printed in U.S.A.  
September, 2000  
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Safety Summary  
The following general safety precautions must be observed during all phases of operation of this instrument. Failure to comply  
with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and  
intended use of the instrument. Agilent Technologies assumes no liability for the customer's failure to comply with these  
requirements.  
WARNING  
Servicing instructions are for use by service-trained personnel. To avoid dangerous electrical shock, do not perform any servicing  
unless you are qualified to do so. Some procedures described in this manual are performed with power supplied to the instrument  
while its protective covers are removed. If contacted, the energy available at many points may result in personal injury.  
BEFORE APPLYING POWER.  
Verify that the product is set to match the available line voltage, the correct line fuse is installed, and all safety precautions (see  
following warnings) are taken. In addition, note the instrument's external markings described under "Safety Symbols"  
GROUND THE INSTRUMENT.  
Before switching on the instrument, the protective earth terminal of the instrument must be connected to the protective conductor  
of the (mains) power cord. The mains plug shall be inserted only in an outlet socket that is provided with a protective earth  
contact. This protective action must not be negated by the use of an extension cord (power cable) that is without a protective  
conductor (grounding). Any interruption of the protective (grounding) conductor or disconnection of the protective earth  
terminal will cause a potential shock hazard that could result in personal injury.  
FUSES  
Only fuses with the required rated current, voltage, and specified type (normal blow, time delay, etc.) should be used. Do not use  
repaired fuses or short-circuited fuseholders. To do so could cause a shock or fire hazard.  
KEEP AWAY FROM LIVE CIRCUITS.  
Operating personnel must not remove instrument covers. Component replacement and internal adjustments must be made by  
qualified service personnel. Do not replace components with power cable connected. Under certain conditions, dangerous  
voltages may exist even with the power cable removed. To avoid injuries, always disconnect power, discharge circuits and  
remove external voltage sources before touching components.  
DO NOT SERVICE OR ADJUST ALONE.  
Do not attempt internal service or adjustment unless another person, capable of rendering first aid and resuscitation, is present.  
Any adjustment, maintenance, and repair of this instrument while it is opened and under voltage should be avoided as much as  
possible. When this is unavoidable, such adjustment, maintenance, and repair should be carried out only by a skilled person who  
is aware of the hazard involved.  
DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT.  
Because of the danger of introducing additional hazards, do not install substitute parts or perform any unauthorized modification  
to the instrument. Return the instrument to an Agilent Technologies Sales and Service Office for service and repair to ensure that  
safety features are maintained.  
SAFETY SYMBOLS  
Refer to the table on the following page  
WARNING The WARNING sign denotes a hazard. It calls attention to a procedure, practice, or the like, which, if not  
correctly performed or adhered to, could result in personal injury. Do not proceed beyond a WARNING sign  
until the indicated conditions are fully understood and met.  
Caution  
The CAUTION sign denotes a hazard. It calls attention to an operating procedure, or the like, which, if not  
correctly performed or adhered to, could result in damage to or destruction of part or all of the product. Do  
not proceed beyond a CAUTION sign until the indicated conditions are fully understood and met.  
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Safety Symbol Definitions  
Description  
Symbol  
Direct current  
Alternating current  
Both direct and alternating current  
Three-phase alternating current  
Earth (ground) terminal  
Protective earth (ground) terminal  
Frame or chassis terminal  
Terminal is at earth potential (Used for measurement and control circuits designed to be  
operated with one terminal at earth potential.)  
Terminal for Neutral conductor on permanently installed equipment  
Terminal for Line conductor on permanently installed equipment  
On (supply)  
Off (supply)  
Standby (supply)  
Units with this symbol are not completely disconnected from ac mains when this switch  
is off. To completely disconnect the unit from ac mains, either disconnect the power  
cord or have a qualified electrician install an external switch.  
In position of a bi-stable push control  
Out position of a bi-stable push control  
Caution, risk of electric shock  
Caution, hot surface  
Caution (refer to accompanying documents)  
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Notice  
The information contained in this document is subject to change without notice. Agilent Technologies makes no  
warranty of any kind with regard to this material, including but not limited to, the implied warranties of  
merchantability, and fitness for a particular purpose.  
Agilent Technologies shall not be liable for errors contained herein or for incidental or consequential  
damages in connection with the furnishing, performance or use of this material.  
This document contains proprietary information which is protected by copyright. All rights are reserved. No part of  
this document may be photocopied, reproduced, or translated into another language without the prior written consent  
of Agilent Technologies.  
ã Copyright 1998, 2000 Agilent Technologies, Inc.  
Printing History  
The edition and current revision of this manual are indicated below. Reprints of this manual containing minor  
corrections and updates may have the same printing date. Revised editions are identified by a new printing date. A  
revised edition incorporates all new or corrected material since the previous printing date.  
Changes to the manual occurring between revisions are covered by change sheets shipped with the manual. In some  
cases, the manual change applies only to specific instruments. Instructions provided on the change sheet will indicate  
if a particular change applies only to certain instruments.  
Edition 1...............................................................June, 1998  
Edition 2...............................................................September, 2000  
Instrument Identification  
The power supply is identified by a unique, two-part serial number, such as, US37450101. The items in this serial  
number are explained as follows:  
US37450101  
The first two letters indicate the country of manufacture. US = United States.  
The next four digits are the year and week of manufacture or last significant design change. Add  
1960 to the first two digits to determine the year. For example, 37=1997. The third and fourth  
digits specify the week of the year (45 = the forty-fifth week).  
The last four digits (0101) are a unique sequential number assigned to each unit.  
5
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Table of Contents  
Warranty Information  
Safety Summary  
Notice  
Printing History  
Instrument Identification  
Table of Contents  
2
3
4
5
5
6
INTRODUCTION  
9
Organization  
9
9
9
10  
10  
10  
10  
Safety Considerations  
Related Documents  
Revisions  
Manual Revisions  
Firmware Revisions  
Electrostatic Discharge  
VERIFICATION AND PERFORMANCE TESTS  
11  
Introduction  
11  
11  
12  
12  
13  
14  
14  
14  
14  
15  
15  
15  
15  
16  
16  
16  
17  
17  
17  
18  
18  
19  
20  
20  
21  
22  
Test Equipment Required  
Measurement Techniques  
Setup for Most Tests  
Electronic Load  
Current-Monitoring Resistor  
Operation Verification Tests  
Performance Tests  
Programming  
Constant Voltage (CV) Tests  
CV Setup  
Voltage Programming and Readback Accuracy  
CV Load Effect  
CV Source Effect  
CV Noise (PARD)  
Transient Recovery Time  
Constant Current (CC) Tests  
CC Setup  
Current Programming and Readback Accuracy  
Current Sink (CC-) Operation  
CC Load and Line Regulation  
CC Load Effect  
CC Source Effect  
CC Noise (PARD)  
Performance Test Equipment Form  
Performance Test Record Form  
TROUBLESHOOTING  
27  
Introduction  
27  
28  
28  
28  
33  
33  
Test Equipment Required  
Overall Troubleshooting  
Flow Charts  
Specific Troubleshooting Procedures  
Power-on Self-test Failures  
6
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CV/CC Status Annunciators Troubleshooting  
Bias and Reference Supplies  
J307 Voltage Measurements  
Manual Fan Speed Control  
34  
34  
35  
36  
36  
37  
37  
37  
38  
38  
38  
38  
39  
39  
40  
40  
40  
41  
41  
41  
42  
Disabling Protection Features  
Post-repair Calibration  
Inhibit Calibration Switch  
Calibration Password  
Initialization  
ROM Upgrade  
Identifying the Firmware  
Upgrade Procedure  
Disassembly Procedures  
List of Required Tools  
Cover, Removal and Replacement  
A2 Interface Board, Removal and Replacement  
Front Panel Assembly, Removal and Replacement  
A3 Front Panel Board, Removal and Replacement  
A1 Main Control Board  
T1 Power Transformer, Removal and Replacement  
Line Voltage Wiring  
PRINCIPLES OF OPERATION  
43  
Introduction  
43  
43  
44  
44  
44  
44  
45  
45  
46  
I/O Interface Signals  
A3 Front Panel Circuits  
A2 Interface Circuits  
Primary Interface  
Secondary Interface  
A1 Main Board Circuits  
Power Circuits  
Control Circuits  
REPLACEABLE PARTS LIST  
49  
Introduction  
49  
DIAGRAMS  
53  
Introduction  
53  
INDEX  
57  
7
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1
Introduction  
Organization  
This manual contains information for troubleshooting and repairing Agilent Models 6611C, 6612C, 6613C and  
6614C System DC Power Supplies. Hereafter all models will be referred to as the dc power supply.  
This manual is organized as follows:  
Chapter 1  
Chapter 2  
Chapter 3  
Chapter 4  
Chapter 5  
Chapter 6  
Organization  
Performance tests  
Troubleshooting procedures  
Principles of operation on a block-diagram level  
Replaceable parts  
Diagrams  
Safety Considerations  
WARNING:  
Hazardous voltages exist within the dc power supply chassis.  
This dc power supply; is a Safety Class I instrument, which means it has a protective earth terminal. This terminal  
must be connected to earth ground through a power source equipped with a 3-wire, ground receptacle. Refer to the  
"Safety Summary" page at the beginning of this manual for general safety information. Before operation or repair,  
check the dc power supply and review this manual for safety warnings and instructions. Safety warnings for specific  
procedures are located at appropriate places in the manual.  
Related Documents  
The following documents are shipped with your dc power supply:  
a a User’s Guide, Agilent part number 5962-8194, containing installation, operating, and calibration information  
a a Programming Guide, Agilent part number 5962-8198, containing detailed GPIB programming information.  
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1 - Introduction  
Revisions  
Manual Revisions  
This manual was written for dc power supplies that have the same manufacturing dates (the first four digits) as those  
listed on the title page and whose unique identification number (the last four digits) are equal to or higher than those  
listed in the title page.  
NOTE:  
1) If the first four digits of the serial number of your unit are higher than those shown in the title  
page, your unit was made after the publication of this manual and may have hardware or firmware  
differences not covered in this manual. If they are significant to the operation and/or servicing of  
the dc power supply, those differences are documented in one or more Manual Change sheets  
included with this manual.  
2) If the first four digits of the serial number of your unit are lower than those shown on the title  
page, your unit was made before the publication of this manual and may be different from that  
described here. Such differences, if any, will be covered in a backdating section in Chapter 6.  
Firmware Revisions  
You can obtain the firmware revision number by either reading the integrated circuit label, or query the dc power  
supply using the GPIB *IDN?' query command (See Chapter 3, ROM Upgrade).  
Electrostatic Discharge  
CAUTION:  
The dc power supply has components that can be damaged by ESD (electrostatic discharge).  
Failure to observe standard antistatic practices can result in serious degradation of performance,  
even when an actual failure does not occur.  
When working on the dc power supply, observe all standard, antistatic work practices. These include, but are not  
limited to:  
a
Working at a static-free station such as a table covered with static-dissipative laminate or with a conductive  
table mat (Agilent P/N 9300-0797, or equivalent).  
a
a
a
Using a conductive wrist strap, such as Agilent P/N 9300-0969 or 9300-0970.  
Grounding all metal equipment at the station to a single common ground.  
Connecting low-impedance test equipment to static-sensitive components only when those  
components have power applied to them.  
a
Removing power from the dc power supply before removing or installing printed circuit boards.  
10  
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2
Verification and Performance Tests  
Introduction  
This document contains test procedures to verify that the dc power supply is operating normally and is within  
published specifications. There are three types of tests as follows:  
Built-in Self Tests  
These tests, run automatically when the power supply is turned on, check most  
of the digital circuits and the programming and readback DACs.  
Operation Verification These tests verify that the power supply is probably operating normally but do  
not check all of the specified operating parameters.  
Performance Tests  
These tests check that the supply meets all of the operating specifications as  
listed in the User’s Guide.  
NOTE:  
The dc power supply must pass the built-in self-tests before calibration or any of the verification  
or performance tests can be performed. If the supply fails any of the tests or if abnormal test results  
are obtained, refer to the troubleshooting procedures in Chapter 3. The troubleshooting procedures  
will determine if repair and/or calibration is required.  
Test Equipment Required  
Table 2-1 lists the equipment required to perform the verification and performance tests. A test record sheet with  
specification limits and measurement uncertainties (when test using the recommended test equipment) may be found  
at the back of this section.  
WARNING:  
SHOCK HAZARD. These tests should only be performed by qualified personnel. During the  
performance of these tests, hazardous voltages may be present at the output of the supply.  
11  
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2 - Verification and Performance Tests  
Table 2-1. Test Equipment Required for Verification and Performance Tests  
Type  
Specifications  
Recommended Model  
Guildline 9230/15  
Current Monitor Resistor 15 A (0.1 ohm) 0.04%  
DC Power Supply  
Digital Voltmeter  
Minimum 5 A output current rating  
Agilent 6632B  
Resolution: 10 nV @ 1V  
Readout: 8 1/2 digits  
Accuracy: 20 ppm  
Agilent 3458A or equivalent  
Electronic Load  
100V, 5 A minimum, with transient capability Agilent 6060B (60V max.), 6063B  
(240V) or equivalent  
GPIB Controller  
Resistors  
Controller with full GPIB capabilities  
400 ohm, 5W  
HP Series 300 or equivalent  
Agilent p/n 0811-1857  
1 ohm, 100 W (or 2 ohm adjustable)  
Ohmite D12K2R0 (2 ohm adjustable)  
(Load resistors may  
substitute for electronic  
load if load is too noisy  
for CC PARD test)  
0.6 ohm, 100W (6611C)  
9 ohm, 100W (6612C)  
49 ohm, 100W (6613C)  
99 ohm, 100W (6614C)  
or an appropriate 150W Rheostat  
Oscilloscope  
Sensitivity: 1 mV  
Bandwidth Limit: 20 MHz  
Probe: 1:1 with RF tip  
Agilent 54504A or equivalent  
Agilent 3400B or equivalent  
RMS Voltmeter  
True RMS  
Bandwidth: 20 MHz  
Sensitivity: 100 µV  
Variable-Voltage  
Transformer  
Adjustable to highest rated input voltage  
range.  
Power: 500 VA  
Measurement Techniques  
Test Setup  
All tests are performed at the rear terminals of the supply as shown in Figure 2-1. Measure the dc voltage directly at  
the +S and -S terminals. Set the Remote/Local switch to Remote and connect the output for remote sensing. Use  
adequate wire gauge for the load leads.  
12  
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Verification and Performance Tests - 2  
SENSE  
SENSE  
Local  
-S  
-
+
+S  
-S  
-
+
+S  
Local  
Remote  
Remote  
NOTE: Connector  
is removable  
+
-
50VDC MAX TO  
+
-
50VDC MAX TO  
Set to  
Set to  
Remote  
Remote  
-
-
DVM, Scope, or  
RMS voltmeter  
(for CV tests)  
DC  
Load  
resistor  
Ampmeter  
400 ohm  
+
+
B.  
-
DVM or  
Current  
monitor  
RMS voltmeter  
SENSE  
Local  
-S  
-
+
+S  
Remote  
(for CC tests)  
+
+
50VDC MAX TO  
-
Set to  
-
+
Remote  
Electronic  
Load  
-
DC  
Load  
resistor  
(see note)  
Ampmeter  
400 ohm  
+
Note: Use dc supply with same polarity  
connectons for - CC tests.  
+
-
Replace electronic load with resistors  
External  
DC supply  
for CC noise test.  
C.  
A.  
Figure 2-1. Test Setup  
Electronic Load  
Many of the test procedures require the use of a variable load capable of dissipating the required power. If a variable  
resistor is used, switches should be used to either; connect, disconnect, or short the load resistor. For most tests, an  
electronic load can be used. The electronic load is considerably easier to use than load resistors, but it may not be  
fast enough to test transient recovery time and may be too noisy for the noise (PARD) tests.  
Fixed load resistors may be used in place of a variable load, with minor changes to the test procedures. Also, if  
computer controlled test setups are used, the relatively slow (compared to computers and system voltmeters) settling  
times and slew rates of the power supply may have to be taken into account. "Wait" statements can be used in the test  
program if the test system is faster than the supply.  
13  
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2 - Verification and Performance Tests  
Current-Monitoring Resistor  
To eliminate output-current measurement error caused by voltage drops in the leads and connections, connect the  
current monitoring resistor between the -OUT and the load as a four-terminal device. Connect the current-monitoring  
leads inside the load-lead connections directly at the monitoring points on the resistor element.  
Operation Verification Tests  
To assure that the supply is operating properly, without testing all specified parameters, perform the turn-on and  
checkout procedures given in the User’s Guide.  
Performance Tests  
NOTE:  
A full Performance Test consists of only those items listed as “Specifications” in Table A-1 of the  
User’s Guide, and that have a procedure in this document.  
The following paragraphs provide test procedures for verifying the supply's compliance with the specifications listed  
in Table A-1 of the User’s Guide. All of the performance test specifications and calculated measurement  
uncertainties are entered in the appropriate Performance Test Record Card for your specific model. You can record  
the actual measured values in the column provided in this card.  
If you use equipment other than that recommended in Table 2-1, you must recalculate the measurement uncertainties  
for the actual equipment used.  
Programming  
You can program the supply from the front panel keyboard or from a GPIB controller when performing the tests. The  
test procedures are written assuming that you know how to program the supply either; remotely from a GPIB  
controller or locally using the control keys and indicators on the supply's front panel. Complete instructions on  
remote and local programming are given in the User’s Guide and in the Programming Guide.  
Table 2-2. Programming and Output Values  
Model  
Full scale  
Vmax  
Full Scale  
Imax  
Isink  
OV Max  
Voltage  
Current  
6611C  
6612C  
6613C  
6614C  
8
20  
50  
100  
8.190  
20.475  
51.187  
102.38  
5
2
1
5.1187  
2.0475  
1.0238  
0.5118  
- 3 A  
8.8  
22  
55  
- 1.2 A  
- 0.6 A  
- 0.3 A  
0.5  
110  
14  
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Verification and Performance Tests - 2  
Constant Voltage (CV) Tests  
CV Setup  
If more than one meter or if a meter and an oscilloscope are used, connect each to the terminals by a separate pair of  
leads to avoid mutual coupling effects. For constant voltage dc tests, connect only to +S and -S, since the unit  
regulates the output voltage that appears between +S and -S, and not between the (+) and (-) output terminals. Use  
coaxial cable or shielded two-wire cable to avoid noise pickup on the test leads.  
Voltage Programming and Readback Accuracy  
This test verifies that the voltage programming, GPIB readback and front panel display functions are within  
specifications. Note that the values read back over the GPIB should be identical to those displayed on the front  
panel.  
a. Turn off the supply and connect a digital voltmeter between the +S and the -S terminals as shown in Figure 2-1a.  
b. Turn on the supply and program the supply to zero volts and the maximum programmable current (Imax in  
Table 2-2) with the load off.  
c. Record the output voltage readings on the digital voltmeter (DVM) and the front panel display. The readings  
should be within the limits specified in the performance test record card for the appropriate model under Voltage  
Programming and Readback @ 0 Volts. Also, note that the CV annunciator is on. The output current reading  
should be approximately zero.  
d. Program the output voltage to full-scale (See Table 2-2) .  
e. Record the output voltage readings on the DVM and the front panel display. The readings should be within the  
limits specified in the performance test record card for the appropriate model under Voltage Programming and  
Readback @ Full Scale.  
CV Load Effect  
This test measures the change in output voltage resulting from a change in output current from full load to no load.  
a. Turn off the supply and connect the output as shown in Figure 2-1a with the DVM connected between the +S  
and -S terminals.  
b. Turn on the supply and program the current to the maximum programmable value (Imax) and the voltage to the  
full-scale value in Table 2-2.  
c. Adjust the load for the full-scale current in Table 2-2 as indicated on the front panel display. The CV  
annunciator on the front panel must be on. If it is not, adjust the load so that the output current drops slightly.  
d. Record the output voltage reading on the DVM connected to +S and -S.  
e. Open the load and again record the DVM voltage reading. The difference between the DVM readings  
in steps (d) and (e) is the load effect voltage, and should not exceed the value listed in the  
performance test record card for the appropriate model under CV Load Effect.  
15  
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2 - Verification and Performance Tests  
CV Source Effect  
This test measures the change in output voltage that results from a change in ac line voltage from the minimum to  
maximum value within the line voltage specifications.  
a. Turn off the supply and connect the ac power line through a variable voltage transformer.  
b. Connect the output as shown in Figure 2-1a with the DVM connected between the +S and the -S terminals. Set  
the transformer to nominal line voltage.  
c. Turn on the supply and program the current to the maximum programmable value (Imax) and the output voltage  
to the full-scale value in Table 2-2.  
d. Adjust the load for the full-scale current value in Table 2-2 as indicated on the front panel display. The CV  
annunciator on the front panel must be on. If it is not, adjust the load so that the output current drops slightly.  
e. Adjust the transformer to the lowest rated line voltage (e.g., 104 Vac for a 115 Vac nominal line voltage input).  
f. Record the output voltage reading on the DVM.  
g. Adjust the transformer to the highest rated line voltage (e.g., 127 Vac for 115 Vac nominal line voltage input).  
h. Record the output voltage reading on the DVM. The difference between the DVM reading is steps (f) and (h) is  
the source effect voltage and should not exceed the value listed in the performance test record card for the  
appropriate model under CV Source Effect.  
CV Noise (PARD)  
Periodic and random deviations (PARD) in the output (ripple and noise) combine to produce a residual ac voltage  
superimposed on the dc output voltage. CV PARD is specified as the rms or peak-to-peak output voltage in the  
frequency range specified in the User’s Guide.  
a. Turn off the supply and connect the output as shown in Figure 2-1a to an oscilloscope (ac coupled) between the  
(+) and the (-) terminals. Set the oscilloscope's bandwidth limit to 20 MHz and use an RF tip on the oscilloscope  
probe.  
b. Turn on the supply and program the current to the maximum programmable value (Imax) and the output voltage  
to the full-scale value in Table 2-2.  
c. Adjust the load for the full-scale current value in Table –2 as indicated on the front panel display.  
d. Note that the waveform on the oscilloscope should not exceed the peak-to-peak limits in the performance test  
record card for the appropriate model under CV Noise (PARD).  
e. Disconnect the oscilloscope and connect an ac rms voltmeter in its place. The rms voltage reading should not  
exceed the RMS limits in the performance test record card for the appropriate model under CV Noise (PARD).  
Transient Recovery Time  
This test measures the time for the output voltage to recover to within the specified value following a 50% change in  
the load current.  
16  
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Verification and Performance Tests - 2  
Loading  
tttt  
Transient  
t
v
v
t
Unloading  
Transient  
Figure 2-2. Transient Waveform  
a. Turn off the supply and connect the output as in Figure 2-1a with the oscilloscope across the +S and -S  
terminals.  
b. Turn on the supply and program the output current to the maximum programmable value (Imax) and the voltage  
to the full-scale value in Table 2-2.  
c. Set the load to the Constant Current mode and program the load current to 1/2 the power supply full-scale rated  
current.  
d. Set the electronic load's transient generator frequency to 100 Hz and its duty cycle to 50%.  
e. Program the load's transient current level to the supply's full-scale current value and turn the transient generator  
on.  
f. Adjust the oscilloscope for a waveform similar to that in Figure 2-2.  
g. The output voltage should return to within the specified voltage (v) in less than 100uS (t). Check both loading  
and unloading transients by triggering on the positive and negative slope. Record the voltage at time “t” in the  
performance test record card under CV Transient Response.  
Constant Current (CC) Tests  
CC Setup  
Follow the general setup instructions in the Measurement Techniques paragraph and the specific instructions given in  
the following paragraphs.  
Current Programming and Readback Accuracy  
This test verifies that the current programming and readback are within specification.  
a. Turn off the supply and connect the current monitoring resistor across the power supply output and the DVM  
across the resistor. See "Current Monitoring Resistor" for connection information.  
b. Turn on the supply and program the output voltage to 5 V and the current to zero amps. The power supply’s  
current detector must be set to DC and the programming language mode to SCPI. See the specifications for high  
range current readback in the User’s Guide if operating with the detector in ACDC or the language in  
Compatibility mode.  
17  
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2 - Verification and Performance Tests  
c. Divide the voltage drop (DVM reading) across the current monitoring resistor by its resistance to convert to  
amps and record this value (Iout). Also, record the current reading on the front panel display. The readings  
should be within the limits specified in the performance test record card for the appropriate model under Current  
Programming and Readback @ 0 Amps.  
d. Program the output current to the full-scale value in Table 2-2.  
e. Divide the voltage drop (DVM reading) across the current monitoring resistor by its resistance to convert to  
amps and record this value (Iout). Also, record the current reading that appears on the front panel display. The  
readings should be within the limits specified in the performance test record card for the appropriate model  
under Current Programming and Readback @ Full Scale.  
Current Sink (-CC) Operation  
This test verifies current sink operation and readback.  
a. Turn off the supply and connect the output as shown in Figure 2-1a, except connect a dc power supply in place  
of the electronic load as indicated. Set the DMM to operate in voltage mode.  
b. Set the external power supply to 5 V and the current to the full scale current rating of the supply under test as in  
Table 2-2.  
c. Turn on the supply under test and program the output voltage to zero and the current to full scale as in Table 2-  
2. The current on the UUT display should be negative and approximately 60% of the current rating.  
d. Divide the voltage drop across the current monitoring resistor by its resistance to obtain the current sink value in  
amps and subtract this from the current reading on the display. The difference between the readings should be  
within the limits specified in the performance test record card under Current Sink Readback.  
Low Range Current Readback Accuracy  
This test verifies the readback accuracy of the 20 milliampere current range.  
a. Turn off the supply and connect the output as shown in Figure 2-1b. Set the DMM to operate in current mode.  
b. Turn on the supply under test and set the current range readback to Low or Auto. Program the output voltage to  
zero and the current to the full scale value in Table 2-2. The current on the UUT display should be  
approximately 0 mA.  
c. Record the current reading on the DMM and the reading on the front panel display. The difference between the  
two readings should be within the limits specified in the performance test record card under 20mA Range  
Current Readback Accuracy @ 0A.  
d. Program the output voltage to 8V and record the current reading on the DMM and the reading on the front  
panel display. If the meter indicates overrange, lower the 8 volts slightly. The difference between the readings  
should be within the limits specified in the performance test record card for the appropriate model under 20mA  
Range Current Readback Accuracy @ +20mA  
e. Turn off the supply and connect the output and an external supply as shown in Figure 2-1c. Set the DMM to  
operate in current mode.  
f. Turn on the external supply and program it to 8V and 1 amp. Then program the supply under test to zero volts  
and 1 amp. If the meter indicates overrange, lower the voltage of the external supply slightly. The UUT display  
should read approximately 20 mA.  
g. Record the current reading on the DMM and the reading on the front panel display. The difference between the  
two readings should be within the limits specified in the performance test record card under 20mA Range  
Current Readback Accuracy @ 20 mA.  
18  
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Verification and Performance Tests - 2  
CC Load and Line Regulation  
These tests (CC Load Effect and CC Source Effect given below) are tests of the dc regulation of the power supply's  
output current. To insure that the values read are not the instantaneous measurement of the ac peaks of the output  
current ripple, several dc measurements should be made and the average of these readings calculated. An example of  
how to do this is given below using an Agilent 3458A System Voltmeter programmed from the front panel. Set up  
the voltmeter and execute the "Average Reading" program follows:  
a. Program 10 power line cycles per sample by pressing NPLC 1 0 ENTER .  
b. Program 100 samples per trigger by pressing (N Rdgs/Trig) 1 0 0 ENTER .  
c. Set up voltmeter to take measurements in the statistical mode as follows:  
Press Shift key, f0, Shift key, N  
Press ^ (up arrow) until MATH function is selected, then press >.  
Press ^ (up arrow until STAT function is selected then press (ENTER).  
d. Set up voltmeter to read the average of the measurements as follows:  
Press Shift key, f1, Shift key, N.  
Press down arrow until RMATH function is selected, then press >.  
Press ^ (up arrow) until MEAN function is selected, then press ENTER.  
e. Execute the program by pressing f0, ENTER, TRIG, ENTER  
f. Wait for 100 readings and then read the average measurement by pressing f1, ENTER.  
To repeat the measurement, perform steps (e) and (f).  
CC Load Effect  
This test measures the change in output current for a change in load from full scale output voltage to short circuit.  
a. Turn off the supply and connect the output as shown in Figure 2-1a with the DVM connected across the current  
monitoring resistor.  
b. Turn on the supply and if it was set to low range readback in the previous test, set it back to high or auto.  
Program the current to full scale and the output voltage to the maximum programmable voltage value (Vmax) in  
Table 2-2.  
c. Adjust the load in the CV mode for the UUT full scale voltage in Table 2-2 as indicated on the front panel  
display. Check that the CC annunciator is on. If it is not, adjust the load so that the output voltage drops slightly.  
d. Record the output current reading (DVM reading/current monitor resistance value in ohms). You may want to  
use the average reading program described under “CC Load and Line Regulation”.  
e. Short the load switch and record the output current reading. The difference in the current readings in steps (d)  
and (e) is the load effect and should not exceed the limit specified in the performance test record card for the  
appropriate model under CC Load Effect.  
19  
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2 - Verification and Performance Tests  
CC Source Effect  
This test measures the change in output current that results when the AC line voltage changes from the minimum to  
the maximum value within the specifications.  
a. Turn off the supply and connect the ac power line through a variable voltage transformer.  
b. Connect the output terminals as shown in Figure 2-1a with the DVM connected across the current monitoring  
resistor. Set the transformer to the nominal line voltage.  
c. Turn on the supply and program the current to the full scale value and the output voltage to the maximum  
programmable value (Vmax) in Table 2-2.  
d. Adjust the load in the CV mode for full scale voltage as indicated on the front panel display. Check that the CC  
annunciator is on. If it is not, adjust the load so that the output voltage drops slightly.  
e. Adjust the transformer to the lowest rated line voltage.  
f. Record the output current reading (DVM reading/current monitoring resistor in ohms). You may want to use the  
average reading program described under “CC Load and Line Regulation”.  
g. Adjust the transformer to the highest rated line voltage.  
h. Record the output current reading again. The difference in the current readings in steps (f) and (h) is the CC  
source effect and should not exceed the values listed in the performance test record card under CC Source  
Effect.  
CC Noise (PARD)  
Periodic and random deviations (PARD) in the output combine to produce a residual ac current, as well, as an ac  
voltage superimposed on the dc output. Constant current (CC) PARD is specified as the rms output current in a  
frequency range 20 Hz to 20 Mhz with the supply in CC operation.  
a. Turn off the supply and connect the load, monitoring resistor, and rms voltmeter as shown in Figure 2-1a. The  
Current Monitoring resistor may have to be substituted by one with a higher resistance and power rating, such as  
a 1 ohm 50W, to get the RMS voltage drop high enough to measure with the RMS voltmeter. Leads should be as  
short as possible to reduce noise pick-up. An electronic load may contribute ripple to the measurement so if the  
RMS noise is above the specification a resistive load may have to be substituted for this test.  
b. Check the test setup for noise with the supply turned off. Other equipment (e.g. computers, DVMs, etc.) may  
affect the reading.  
c. Turn on the supply and program the current to full scale and the output voltage to the maximum programmable  
value (Vmax) in Table 2-2.  
d. The output current should be at the full scale rating with the CC annunciator on.  
e. Divide the reading on the rms voltmeter by the load resistance to obtain rms current. It should not exceed the  
values listed in the performance test record card under CC Noise (RMS).  
20  
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Verification and Performance Tests - 2  
Performance Test Equipment Form  
Test Facility:_________________________  
____________________________________  
____________________________________  
____________________________________  
Model ______________________________  
Serial No. ____________________________  
Options _____________________________  
Firmware Revision ____________________  
Special Notes:  
Report Number ________________________  
Date _________________________________  
Customer _____________________________  
Tested By ____________________________  
Ambient Temperature (C) ________________  
Relative Humidity (%) ___________________  
Nominal Line Frequency __________________  
Test Equipment Used:  
Description  
Model No.  
Trace No.  
Cal. Due Date  
AC Source  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
_________________  
DC Voltmeter  
RMS Voltmeter  
Oscilloscope  
Electronic Load  
Current Shunt  
21  
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2 - Verification and Performance Tests  
Performance Test Record Form  
Model Agilent 6611C  
Test Description  
Report No _______________ Date __________________  
Minimum  
Specs.  
Results*  
Maximum  
Specs.  
Measurement  
Uncertainty  
Constant Voltage Tests  
Voltage Programming and Readback  
Low Voltage (0V) Vout  
__________  
__________  
__________  
__________  
+ 5 mV  
Vout + 2 mV  
8.009 V  
5 mV  
Vout 2 mV  
7.991 V  
1.6 µV  
1.6 µV  
335 µV  
335 µV  
20 µV  
Front Panel Display Readback  
High Voltage (Full Scale) Vout  
Front Panel Display Readback  
Vout + 4.4 mV  
Vout 4.4mV  
Load Effect  
__________ Vout + 2.0mV  
__________ Vout + 0.5 mV  
Vout 2.0mV  
Vout 0.5mV  
Source Effect  
20 µV  
PARD (Ripple and Noise)  
Peak-to-Peak  
__________  
__________  
Vout + 3 mV  
Vout 3 mV  
Vout 0.5mV  
872 µV  
50 µV  
RMS  
Vout + 0.5 mV  
Transient Response  
__________ Vout + 20 mV  
3 mV  
Time in 100 µs  
Vout 20 mV  
Constant Current Tests  
Current Programming and Readback  
Low current (0A) Iout  
__________  
__________  
__________  
__________  
+ 2.0 mA  
Iout + 0.5 mA  
5.0045 A  
2.0 mA  
Iout 0.5 mA  
4.9955 A  
15.2 µA  
15.2 µA  
252 µA  
252 µA  
200 µA  
Readback Accuracy @ Iout  
High Current (Full Scale) Iout  
Readback Accuracy @ Iout  
Iout + 10.5mA  
Iout 10.5mA  
Current Sink (@ -3A) Readback  
__________ Iout + 7.1 mA  
Iout 7.1 mA  
20 mA Range Current Readback  
Readback Accuracy @ 0 A  
__________  
__________  
__________  
2.5 µA  
+ 2.5 µA  
0.1 µA  
1.7 µA  
1.7 µA  
Readback Accuracy @ + 20 mA  
Readback Accuracy @ 20 mA  
Iout 22.5 µA  
Iout 22.5 µA  
Iout + 22.5 µA  
Iout + 22.5 µA  
PARD (Current Ripple and Noise)  
RMS  
__________  
__________  
__________  
+ 2.0 mA  
+ 1 mA  
2.0 mA  
1 mA  
200 µA  
1.6 µA  
1.6 µA  
Load Effect  
Source Effect  
+ 0.5 mA  
0.5 mA  
22  
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Verification and Performance Tests - 2  
Model 6612C  
Report No _______________ Date __________________  
Test Description  
Minimum  
Specs.  
Results*  
Maximum  
Specs.  
Measurement  
Uncertainty  
Constant Voltage Tests  
Voltage Programming and Readback  
Low Voltage (0V) Vout  
__________  
__________  
__________  
__________  
+ 10 mV  
Vout + 3 mV  
20.020 V  
10 mV  
Vout 3 mV  
19.980 V  
1.6 µV  
1.6 µV  
335 µV  
335 µV  
20 µV  
Front Panel Display Readback  
High Voltage (Full Scale) Vout  
Front Panel Display Readback  
Vout + 9 mV  
Vout 9 mV  
Load Effect  
__________ Vout + 2.0mV  
__________ Vout + 0.5 mV  
Vout 2.0 mV  
Vout 0.5 mV  
Source Effect  
20 µV  
PARD (Ripple and Noise)  
Peak-to-Peak  
__________  
__________  
Vout + 3 mV  
Vout 3 mV  
872 µV  
50 µV  
RMS  
Vout + 0.5 mV  
Vout 0.5 mV  
Transient Response  
__________ Vout + 20 mV  
3 mV  
Time in 100 µs  
Vout 20 mV  
Constant Current Tests  
Current Programming and Readback  
Low current (0A) Iout  
__________  
__________  
__________  
__________  
+ 1.0 mA  
Iout + 0.25 mA  
2.002 A  
1.0 mA  
Iout 0.25 mA  
1.998 A  
15.2 µA  
15.2 µA  
252 µA  
252 µA  
200 µA  
Readback Accuracy @ Iout  
High Current (Full Scale) Iout  
Readback Accuracy @ Iout  
Iout + 4.3 mA  
Iout 4.3 mA  
Current Sink (@ -1.2A) Readback  
__________ Iout + 3.3 mA  
Iout 3.3 mA  
20 mA Range Current Readback  
Readback Accuracy @ 0 A  
__________  
__________  
__________  
2.5 µA  
+ 2.5 µA  
0.1 µA  
1.7 µA  
1.7 µA  
Readback Accuracy @ + 20 mA  
Readback Accuracy @ 20 mA  
Iout 22.5 µA  
Iout 22.5 µA  
Iout + 22.5 µA  
Iout + 22.5 µA  
PARD (Current Ripple and Noise)  
RMS  
__________  
__________  
__________  
+ 1.0 mA  
+ 0.5 mA  
+ 0.5 mA  
1.0 mA  
0.5 mA  
0.5 mA  
200 µA  
1.6 µA  
1.6 µA  
Load Effect  
Source Effect  
23  
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2 - Verification and Performance Tests  
Model Agilent 6613C  
Test Description  
Report No _______________ Date __________________  
Minimum  
Specs.  
Results*  
Maximum  
Specs.  
Measurement  
Uncertainty  
Constant Voltage Tests  
Voltage Programming and Readback  
Low Voltage (0V) Vout  
__________  
__________  
__________  
__________  
+ 20 mV  
Vout + 6 mV  
50.045 V  
20 mV  
Vout 6 mV  
49.955 V  
1.6 µV  
1.6 µV  
335 µV  
335 µV  
20 µV  
Front Panel Display Readback  
High Voltage (Full Scale) Vout  
Front Panel Display Readback  
Vout + 21 mV  
Vout 21 mV  
Load Effect  
__________ Vout + 4 mV  
__________ Vout + 1 mV  
Vout 4 mV  
Vout 1 mV  
Source Effect  
20 µV  
PARD (Ripple and Noise)  
Peak-to-Peak  
__________  
__________  
Vout + 4 mV  
Vout 4 mV  
Vout 0.5mV  
872 µV  
50 µV  
RMS  
Vout + 0.5 mV  
Transient Response  
__________ Vout + 50 mV  
3 mV  
Time in 100 µs  
Vout 50 mV  
Constant Current Tests  
Current Programming and Readback  
Low current (0A) Iout  
__________  
__________  
__________  
__________  
+ 0.5 mA  
Iout + 0.2 mA  
1.001 A  
0.5 mA  
Iout 0.2 mA  
0.999 A  
15.2 µA  
15.2 µA  
252 µA  
252 µA  
200 µA  
Readback Accuracy @ Iout  
High Current (Full Scale) Iout  
Readback Accuracy @ Iout  
Iout + 2.2 mA  
Iout 2.2 mA  
Current Sink (@ -0.6A) Readback  
__________ Iout + 2 mA  
Iout 2 mA  
20 mA Range Current Readback  
Readback Accuracy @ 0 A  
__________  
__________  
__________  
2.5 µA  
+ 2.5 µA  
0.1 µA  
1.7 µA  
1.7 µA  
Readback Accuracy @ + 20 mA  
Readback Accuracy @ 20 mA  
Iout 22.5 µA  
Iout 22.5 µA  
Iout + 22.5 µA  
Iout + 22.5 µA  
PARD (Current Ripple and Noise)  
RMS  
__________  
__________  
__________  
+ 1.0 mA  
+ 0.5 mA  
+ 0.25mA  
1.0 mA  
0.5 mA  
0.25mA  
200 µA  
1.6 µA  
1.6 µA  
Load Effect  
Source Effect  
24  
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Verification and Performance Tests - 2  
Model Agilent 6614C  
Test Description  
Report No _______________ Date __________________  
Minimum  
Specs.  
Results*  
Maximum  
Specs.  
Measurement  
Uncertainty  
Constant Voltage Tests  
Voltage Programming and Readback  
Low Voltage (0V) Vout  
__________  
__________  
__________  
__________  
+ 50 mV  
Vout + 12 mV  
100.100 V  
50 mV  
Vout 12 mV  
99.900 V  
1.6 µV  
1.6 µV  
335 µV  
335 µV  
20 µV  
Front Panel Display Readback  
High Voltage (Full Scale) Vout  
Front Panel Display Readback  
Vout + 42 mV  
Vout 42 mV  
Load Effect  
__________ Vout + 5 mV  
__________ Vout + 1 mV  
Vout 5 mV  
Vout 1 mV  
Source Effect  
20 µV  
PARD (Ripple and Noise)  
Peak-to-Peak  
__________  
__________  
Vout + 5 mV  
Vout 5 mV  
872 µV  
50 µV  
RMS  
Vout + 0.5 mV  
Vout 0.5 mV  
Transient Response  
__________ Vout + 100mV  
3 mV  
Time in 100 µs  
Vout 100mV  
Constant Current Tests  
Current Programming and Readback  
Low current (0A) Iout  
__________  
__________  
__________  
__________  
+ 0.25 mA  
Iout + 0.1 mA  
0.5005 A  
0.25 mA  
Iout 0.1 mA  
0.4995 A  
15.2 µA  
15.2 µA  
252 µA  
252 µA  
200 µA  
Readback Accuracy @ Iout  
High Current (Full Scale) Iout  
Readback Accuracy @ Iout  
Iout + 1.1 mA  
Iout 1.1 mA  
Current Sink (@ -0.3A) Readback  
__________ Iout + 1.3 mA  
Iout 1.3 mA  
20 mA Range Current Readback  
Readback Accuracy @ 0 A  
__________  
__________  
__________  
2.5 µA  
+ 2.5 µA  
0.1 µA  
1.7 µA  
1.7 µA  
Readback Accuracy @ + 20 mA  
Readback Accuracy @ 20 mA  
Iout 22.5 µA  
Iout 22.5 µA  
Iout + 22.5 µA  
Iout + 22.5 µA  
PARD (Current Ripple and Noise)  
RMS  
__________  
__________  
__________  
+ 1.0 mA  
+ 0.5 mA  
+ 0.25mA  
1.0 mA  
0.5 mA  
0.25mA  
200 µA  
1.6 µA  
1.6 µA  
Load Effect  
Source Effect  
* Enter your test results in this column  
25  
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3
Troubleshooting  
Introduction  
WARNING:  
SHOCK HAZARD. Most of the troubleshooting procedures given in this chapter are  
performed with power applied and protective covers removed. Such maintenance should  
be performed only by service trained personnel who are aware of the hazards (for  
example, fire and electrical shock).  
CAUTION:  
This instrument uses components which can either be damaged or suffer serious  
performance degradation as a result of ESD (electrostatic discharge). Observe the  
standard antistatic precautions to avoid damage to the components. An ESD summary is  
given in Chapter 1.  
This chapter provides troubleshooting and repair information for the dc power supply. Before attempting to  
troubleshoot the supply, first check that the problem is with the supply itself and not with an associated  
circuit. The verification tests in Chapter 2 enable you to isolate a problem to the dc power supply.  
Troubleshooting procedures are provided to isolate a problem to one of the circuit boards. Figure 3-2 shows  
the location of the circuit boards and other major components of the unit. Disassembly procedures are  
provided at the end of this chapter and should be referred to, as required, in order to gain access to and/or  
replace defective components.  
If an assembly is defective, replace it and then conduct the verification test given in Chapter 2.  
NOTE:  
Note that when either the A1 Control Board or the A2 Interface Board are replaced, the  
supply must be calibrated (See "Post Repair Calibration" later in this chapter). If the A2  
Interface Board is replaced, the supply must be initialized before it is calibrated. See  
"Initialization" later in this chapter.  
Chapter 5 lists all of the replaceable parts for the power supply. Chapter 6 contains block diagrams, test  
point measurements, and component location diagrams to aid you in troubleshooting the supply.  
27  
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3 - Troubleshooting  
Test Equipment Required  
Table 3-1 lists the test equipment required to troubleshoot the power supply. Recommended models are  
listed.  
Table 3-1. Test Equipment Required for Troubleshooting  
Type  
Purpose  
Recommended Model  
GPIB Controller  
To communicate with the supply via the  
GPIB interface  
HP Series 200/300  
Digital Voltmeter  
Oscilloscope  
To check various voltage levels  
To check waveforms and signal levels  
To test operation of current circuit  
Agilent 3458A  
Agilent 54504A/54111A  
Electronic Load  
Agilent 6060B (60V) or 6063B  
(240V)  
Ammeter/Current  
Shunt  
To measure output current  
Guildline 9230/15  
Overall Troubleshooting  
Overall troubleshooting procedures for the power supply are given in the Figure 3-1. The procedures first  
check that neither an AC input, nor a bias supply failure is causing the problem and that the supply passes  
the turn-on self test (error annunciator stays off). The normal turn-on, self-test indications are described in  
the "Checkout Procedure" in Chapter 3 of the User's Guide.  
If the supply passes the self test and there are no obvious faults, you should perform the verification  
procedures in Chapter 2 from the front panel to determine if any functions are not calibrated or are not  
operating properly. Then program and read back a voltage via the GPIB to see if the supply responds  
properly to bus commands. If the supply fails any of the tests, you will be directed to the applicable flow  
chart or troubleshooting procedure.  
Flow Charts  
Troubleshooting flow charts are given in Figure 3-1 sheets 1-4. The flow charts make reference to the test  
points listed in Chapter 6. The circuit locations of the test points are shown on the component location  
diagrams in Chapter 6.  
28  
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Troubleshooting - 3  
Turn on unit and observe the  
display. All of the segments and  
annunciators, the address and  
then after self test should display  
an error message or go to the  
metering mode.  
Check Bias voltages  
(see Table 3-3)  
Check Main Fuse,  
Replace T1  
No  
No  
Bias voltages OK?  
Yes  
Transformer Inputs  
OK?  
Yes  
Replace A1  
Check A1F305,  
Red/White/Black  
No  
+5V @ A2J211-1 (to  
chassis)?  
No  
Display comes on?  
Yes  
cable A1-A2 &  
cable A2-A3, track  
on A2 (J206-J211)  
Yes  
Go to Error Message  
Table 3-2.  
Yes  
Error Message?  
A3J111-5 low (no  
pulses)?  
No  
Replace A3  
No  
Yes  
Protect  
annunciator  
on?  
Yes  
Yes  
RI?  
No  
Replace A2  
Check for OV setting <  
Voltage setting, Replace  
A1  
Yes  
Yes  
Yes  
OV?  
No  
Check that OCP is not  
enabled, Replace A1  
OC?  
No  
No  
Check F309 (fuse near  
main heat sink),  
Replace A1  
FS?  
No  
For OT check fan,  
Replace A1  
Go to Sheet 2  
Figure 3-1 Sheet 1. Troubleshooting Flowchart  
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3 - Troubleshooting  
From Sheet 1  
Enable output and  
program voltage and  
current full scale with no  
load. Measure output  
voltage.  
Check to insure OV  
setting is not less than  
the voltage setting. If not  
then replace A1.  
Yes  
Yes  
Unit OV's?  
No  
CV_Prog &  
CC_Prog OK? (see  
Table 3-4)  
Output voltage  
> 10% error?  
Check cable W9,  
Replace A1  
Yes  
No  
No  
Replace A2  
Output out of spec  
but close?  
Yes  
Calibrate voltage  
No  
Calibrate voltage. If  
still wrong or will not  
calibrate, replace A2  
Output OK but  
meter wrong?  
Yes  
No  
Program the OV 2  
volts lower than the  
output voltage.  
Calibrate OV. If OV is still  
not functioning properly  
check W9, replace A1.  
Program OV to  
full scale  
OV_Prog OK?  
(see Table 3-4)  
No  
Yes  
Unit OV's?  
Yes  
No  
Replace A2  
Go to Sheet 3  
Figure 3-1 Sheet 2. Troubleshooting Flowchart  
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Troubleshooting - 3  
From Sheet 2  
Program current to full  
scale, voltage to Vmax  
and load to the power  
supply's rated current.  
Supply should be in CC.  
CC_Prog OK ?  
(see Table 3-4)  
Yes  
Replace A1  
Yes  
Will not go into CC  
or error > 10%  
?
No  
No  
Replace A2  
Yes  
Output out of spec  
but close?  
Calibrate unit  
No  
Calibrate current. If still  
wrong or will not  
calibrate, replace A2  
Output OK but  
meter wrong?  
Yes  
No  
Turn on OCP and  
insure Protect trips.  
CC_detect* low?  
(see Table 3-4)  
Check cable W9,  
replace A1  
No  
No  
Prot trips?  
Yes  
Replace A2  
Yes  
Goto Sheet 4  
Figure 3-1 Sheet 3. Troubleshooting Flowchart  
31  
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3 - Troubleshooting  
From Sheet 3  
Connect controller to the  
HPIB port and send  
commands to set the  
output voltage and  
current and readback the  
output.  
No  
Accepts and reads  
back?  
Replace A2  
Yes  
Run the Performance  
Test in Chapter 2.  
Regulation, Transient  
Response and ripple  
problems are generally  
caused by A1  
No  
Passes test?  
Yes  
Short RI terminals on  
rear of supply and insure  
output disables and Prot  
annunciator comes on.  
No  
Remote Inhibit  
OK?  
Replace A2  
Yes  
There is either no fault  
with the power supply or  
the problem is not  
covered by this  
procedure.  
Figure 3-1 Sheet 4. Troubleshooting Flowchart  
32  
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Troubleshooting - 3  
Specific Troubleshooting Procedures  
Power-on Self-test Failures  
The power-on self-test sequence tests most of the digital and DAC circuits. If the supply fails self-test, the  
display "ERR" annunciator will come on. You can then query the unit to find out what the error(s) are.  
When an error is detected, the output is not disabled so you can still attempt to program the supply to help  
troubleshoot the unit. Table 3-2 lists the self test errors and gives the probable cause for each error.  
NOTE:  
A partial self test is performed when the *TST? query is executed. Those tests that  
interfere with normal interface operation or cause the output to change are not performed  
by *TST?. The return value of *TST? will be zero if all tests pass, or the error code of the  
first test that failed. The power supply will continue normal operation if *TST? returns a  
non-zero value.  
Table 3-2. Self-Test Error Codes/Messages  
Error Code Description  
Probable Cause  
A2 Interface Bd  
A2 Interface Bd  
A2 Interface Bd  
A2 Interface Bd  
A2 Interface Bd  
A2 Interface Bd  
E1  
Checksum in Read-only Non-volatile ROM  
E2  
Checksum in Config Non-volatile ROM  
Checksum in Cal Non-volatile ROM  
Checksum in State Non-volatile ROM  
Checksum in RST Non-volatile ROM  
RAM test failed  
E3  
E4  
E5  
E10  
E11  
12 bit DAC test failed, 0 is written to DAC U241A and B, A2 Interface Bd  
ADC U242 is checked for 133 +/- 7 counts  
E12  
E13  
E14  
E15  
E80  
12 bit DAC test failed, 4095 is written to DAC U241A  
and 0 to B, ADC U242 is checked for 71 +/- 7 counts  
A2 Interface Bd  
A2 Interface Bd  
A2 Interface Bd  
A2 Interface Bd  
A2 Interface Bd  
12 bit DAC test failed, 0 is written to DAC U241A and  
4095 to B, ADC U242 is checked for 71 +/- 7 counts  
12 bit DAC test failed, 4095 is written to DAC U241A  
and B, ADC U242 is checked for 10 +/- 7 counts  
8 bit DAC test failed, 10 and 240 are written to DAC  
U244, ADC U242 is checked for 10 and 240 +/- 7 counts  
Dig I/O test failed, SEC_PCLR written low and high,  
read back through Xilinx  
E213  
E216  
E217  
E218  
E220  
RS-232 input buffer overrun  
RS-232 framing error  
A2 Interface Bd  
A2 Interface Bd  
RS-232 parity error  
A2 Interface Bd  
RS-232 UART input overrun  
Front Panel comm UART input overrun  
A2 Interface Bd  
A3 Front Panel/Display Bd  
33  
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3 - Troubleshooting  
E221  
E222  
E223  
Front Panel comm UART framing error  
A3 Front Panel/Display Bd  
A3 Front Panel/Display Bd  
A3 Front Panel/Display Bd  
Front Panel comm UART parity error  
Front Panel firmware input buffer overrun  
CV/CC Status Annunciators Troubleshooting  
The CV/CC annunciators are particularly helpful when troubleshooting a unit with no output voltage or  
current. If the unit has passed self test the programming DAC circuits on the A2 circuit board are probably  
working properly. If either the CV or CC annunciators is on then the problem is in either the CV or CC  
control circuits located on the A1 Main board. If UNR is indicated then neither the voltage nor the current  
circuits are in control and the problem would be in the main power transformer or the driver or output  
regulator stages circuits, also on A1 but after the gating diodes.  
Bias and Reference Supplies  
Before troubleshooting any circuit check the bias and/or reference voltages to make sure that they are not  
the cause. Table 3-3 lists the bias and reference voltage test points for the A1 Main Control , A2 Interface,  
and the A3 Front Panel/Display boards. Unless otherwise noted, all voltages are measured with respect to  
secondary common (R431-3) with no load on the supply. See Figure 6-1 for test point locations.  
Table 3-3. Bias and Reference Voltages  
Bias  
Test Point  
Measurement  
+5V primary 1  
+5V primary (unreg) 1  
+5V secondary 2  
+15V secondary 2  
-15V secondary 2  
6611C +Rail 3  
6612C +Rail 3  
6613C +Rail 3  
6614C +Rail 3  
-Rail 3  
A1 E320(Red wire)  
A1 E3321(White wire)  
A1 R423 (jumper)  
A1 R419 (jumper)  
A1 R422 (jumper)  
A1 Main Heat Sink  
A1 Main Heat Sink  
A1 Main Heat Sink  
A1 Main Heat Sink  
A1 D307 Anode  
+5V +/- 0.15V  
+5V  
+5V +/- 0.2V  
+15V +/- 0.6V  
-15V +/- 0.6V  
+20V +/- 10% (50mV P/P)  
+32V +/- 10% (120mV P/P)  
+81V +/- 10% (300mV P/P)  
+130V +/- 10% (400mV P/P)  
-6.8 to - 9.1V (100mV P/P)  
1 Measured with respect to Primary common (Black wire at A1 E324).  
2 Measured with respect to Secondary common (R431-3).  
3 Measured with respect to - Output at nominal ac input line voltage.  
34  
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Troubleshooting - 3  
J307 Voltage Measurements  
Cable W9 connects J307 of the A1 Main Board Assembly to J207 of the A2 Interface Assembly. Table 3-4  
provides a quick method of determining if the voltages between these assemblies are within the normal  
range. If any of these voltages is outside the normal range, refer to the flowcharts to further troubleshoot the  
circuit associated with the abnormal voltage.  
Table 3-4. Voltage Measurements at J207 (A2 Interface to A1 Main board)  
A1J207  
Pin #  
Signal Name  
CV Mode  
Full Scale Voltage  
No Load  
CC Mode  
Full Scale Voltage  
Full Load  
1
2
3
4
5
6
7
8
PM_INHIBIT (Enabled)  
OV_SCR*  
0
+5  
0
+5  
OV_PROG  
+3.9  
+2.8  
+5  
+3.9  
+3.8  
+5  
FAN_PROG  
OV_DETECT*  
SW_POS (Norm)  
RANGE_SELECT (High)  
OS_TRIM_NEG (COMP)  
OS_TRIM_NEG (SCPI)  
+5Vs  
+5  
+5  
0
0
+1.7  
+4.0  
+5  
+1.7  
+4.0  
+5  
9
10  
11  
12  
13  
14  
15  
16  
17  
COMMON  
0
0
COMMON  
0
0
+15Vs  
+15  
-15  
+2.5  
+2.4  
0
+15  
-15  
+2.5  
+2.6  
+3.5  
-15Vs  
HS_THERM (@25C)  
FUSE  
IMON_H  
IMON_L  
IMON_L (@20mA Out)  
0
+4.8  
+14.7  
+4.8  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27  
28  
IMON_P  
0
+4.8  
0
0
+4.8  
0
VMON  
COMMON  
COMMON  
COMMON  
COMMON  
CV_PROG  
CC_PROG  
CC_DETECT*  
CCN_DETECT*  
CV_DETECT*  
0
0
0
0
0
0
-4.8  
-4.8  
+5  
+5  
0
-4.8  
-4.8  
0
+5  
+5  
35  
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3 - Troubleshooting  
Manual Fan Speed Control  
Under some circumstances such as testing acoustical devices where the fan noise would interfere with the  
test, it would be advantageous to reduce the fan speed. If the test requires a very light load, the ambient  
temperature is low and the duration of the test is short, the fan speed may be temporarily reduced. The turn-  
on default is "Automatic" so this procedure must be performed, as needed, every time the line voltage is  
turned on. To manually control the fan speed:  
a. Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.  
b. Using the Up/Down annunciator keys select FAN:MODE<AUTO.>.  
c. Using the Up/Down arrows select FAN:MODE <MAN>  
d. Press "Enter"  
e. Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.  
f.  
Using the Up/Down annunciator keys select FAN:SPEED <data>  
g. Press "Enter Number".  
h. Enter the desired speed (numeric entry range is 0 to 100%)  
i.  
Press "Enter"  
Disabling Protection Features  
The power supply's protection features may be disabled. This is not recommended as a normal operating  
condition but is helpful under some circumstances such as troubleshooting. The turn-on default is "NO-  
PROTECT OFF" (protection enabled) so this procedure must be performed, as needed, every time the line  
voltage is turned on. The overvoltage protection function is not disabled by this procedure. To disable the  
protection:  
a. Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.  
b. Using the Up/Down annunciator keys select NO-PROTECT <OFF>.  
c. Using the Up/Down arrows select NO-PROTECT <ON>.  
d. Press "Enter"  
36  
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Troubleshooting - 3  
Post-repair Calibration  
Calibration is required annually and whenever certain components are replaced. If either A1 or A2 are  
replaced, the supply must be re-calibrated as described in Appendix B of the User's Guide.  
If the Interface board A2 is replaced, the supply must be initialized first (see "Initialization" later in this  
chapter) and then be calibrated.  
Inhibit Calibration Switch  
If "CAL DENIED" appears on the display when calibration is attempted, or if error code 401 occurs when  
calibrating over the GPIB, the internal INHIBIT CAL switch has been set. This switch setting prevents  
unauthorized or inadvertent power supply calibration. You must reset this switch in order to calibrate the  
supply.  
This four-section switch, S201, is located on the A2 Interface board near the GPIB connector. The switch  
has 2 functions related to calibration. One is Inhibit Calibration. With this switch set the supply will not  
respond to calibration commands, thus providing security against unauthorized calibration. The other  
switch allows you to bypass the password in case it is forgotten.  
Switch 3 Switch 4  
4 3 2 1  
Off  
Off  
Off  
On  
Normal  
Clear  
Password  
ON  
On  
Off  
Inhibit  
Calibration  
S201  
Calibration Password  
In order to enter the calibration mode, you must use the correct password as described in Appendix B of  
the User’s Guide. As shipped from the factory, the number 0 (zero) is the password. If you use an incorrect  
password, "OUT OF RANGE" will appear on the display for front panel calibration (or error code 402  
occurs for GPIB calibration) and the calibration mode will not be enabled.  
If you have changed the password and have forgotten it, you can set the configuration switch on A2  
Interface board to bypass the password. See "Calibration Switch" paragraph above.  
37  
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3 - Troubleshooting  
Initialization  
The dc power supply's GPIB address and model number as well as other constants which are required to  
program and calibrate the supply are stored in a EEPROM on the A2 Interface board. The Interface board  
also contains references and other components that will affect the alignment of the supply. If the Interface  
board is replaced, the supply must be reinitialized and calibrated. To initialize the power supply:  
a. Enable the Calibration mode  
b. Simultaneously depress the "0" and "1" keys.  
c. Using the Up/Down arrows select the appropriate model number  
d. Press "Enter"  
The dc power supply will go through the turn-on self test sequence. It is now re-initialized and must be  
calibrated. See Appendix A of the User’s Guide for the calibration procedure.  
ROM Upgrade  
Identifying the Firmware  
You can use the *IDN? query to identify the revision of the supply's firmware. The query will readback the  
revisions of the Primary Interface ROM located on the A2 Interface board. The manufacturer and model  
number of the supply are also returned. The following is a sample program:  
10  
20  
30  
40  
50  
ALLOCATE L$[42]  
OUTPUT 705;"*IDN?"  
ENTER 705;L$  
DISP L$  
END  
The computer will display the manufacturer's name, the model number, a "0," and then the firmware  
revision. Example: "AGILENT TECHNOLGIES,66312A,0,A.00.01". The revision level of the ROM can  
also be found on the label affixed to the physical IC chip itself.  
Upgrade Procedure  
If the Interface board ROM is upgraded you can re-initialize the supply without affecting the calibration.  
a. Enable the Calibration mode.  
b. Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.  
c. Using the Up/Down annunciator keys select ROMUPD <model>.  
d. Using the Up/Down arrows select the appropriate model number.  
e. Press "Enter".  
The supply will go through the turn-on self test sequence and return to the power supply metering mode.  
38  
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Troubleshooting - 3  
Disassembly Procedures  
The following paragraphs provide instructions on how to disassemble various components of the dc power  
supply. Once disassembled, the components can be reassembled by performing the disassembly  
instructions in reverse order. Figure 3-2 shows the location of the major components of the unit.  
Figure 3-2. Component Location  
WARNING:  
CAUTION:  
SHOCK HAZARD. To avoid the possibility of personal injury, turn off AC power and  
disconnect the line cord before removing the top cover. Disconnect the GPIB cable and  
any loads, and remote sense leads before attempting disassembly.  
Most of the attaching hardware is metric. Use of other types of fasteners will damage  
threaded inserts. Refer to the list of required tools when performing disassembly and  
replacement.  
List of Required Tools  
a. 2PT Pozidriv screwdrivers.  
b. T10 and T15 Torx screwdrivers.  
c. Hex drivers: 7 mm for GPIB connector,  
3/16" for RS-232 connector,  
1/4" for front panel binding posts  
d. Long nose pliers.  
e. Antistatic wrist discharge strap.  
39  
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3 - Troubleshooting  
Cover, Removal and Replacement  
a. Using a T15 Torx screwdriver, unscrew the two captive screws which hold the rear bezel to the dc  
power supply, and then remove the two screws from the bottom of the case.  
b. Slide the cover backward until it clears the rear of the power supply.  
A2 Interface Board, Removal and Replacement  
To remove the Interface Board, proceed as follows:  
a. Remove the cover of the power supply as described under, "Cover Removal and Replacement."  
b. Remove the two 7 mm and two 3/16 inch hex screws that hold the GPIB and RS-232 connectors in  
place.  
c. Slide the board forward and lift the right side of the board and slide it out.  
d. Unplug the 3 conductor cable from J206. Depress the release button located at the end of the connector  
where the wires enter the housing.  
e. Unplug the flat cables. Note the position of the conductive side for reinstallation. Connectors release  
the cable by pulling out end tabs as shown by the arrows in the following figure.  
f. To reinstall the Interface board, perform the above steps in reverse order.  
Front Panel Assembly, Removal and Replacement  
This procedure removes the front panel assembly from the dc power supply.  
a. Remove the Power Supply Cover as described earlier in, "Top Cover Removal and Replacement."  
b. Disconnect the cable between the Front Panel board and the Interface board at the Interface board. You  
may have to remove the Interface board as described above to accomplish this.  
c. Using a Torx T10 driver remove the screw from the right side of the supply that holds the front panel  
bracket to the chassis.  
d
Unplug the Binding Post cable.  
e. Locate and carefully peel off the left vinyl trim to gain access to the side screw that secures the front  
panel to the chassis. Using a Torx T15 driver remove the screw located behind the vinyl trim.  
f. Place the power switch in the on position and slide the switch extension forward as far as it can go and  
lift up to disengage from switch. Remove extension from the unit.  
g. Rotate front panel forward from right side to disengage left mounting studs and pull forward.  
h. To remove the right bracket, depress the plastic tab located behind the front panel in the upper right  
corner.  
i. To reinstall the Front Panel Assembly, perform the above steps in reverse order.  
40  
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Troubleshooting - 3  
A3 Front Panel Board, Removal and Replacement  
First remove the front panel assembly as described under, "Front Panel Assembly, Removal and  
Replacement." Once you have access to the front panel board perform these steps:  
a. Remove the RPG knob by pulling it away from the front panel.  
b. Pull back the right side of the board near the RPG about 1/8th of an inch. Slide the board to the left to  
disengage the holding clips.  
c. To reinstall the Front Panel board, perform the above steps in reverse order.  
A1 Main Control Board  
a. Remove the top cover and the A2 Interface board as described above.  
b. Disconnect all cables going to connectors on the main control board.  
NOTE:  
Be sure to note the position and orientation of all cables prior to removal so that no  
mistake is made later when reinstalling these cables.  
c. Disconnect the ground wire between the main board and the chassis. This wire is secured to the side of  
the chassis near the AC input by a Torx T10 screw.  
d. Remove two Torx T15 screws which secure the main control board to the chassis.  
e. Remove the Torx 15 screw that holds the main rectifier in the front right corner of the board.  
f. Slide the main board towards the front panel to release it from chassis mounted standoff and then lift  
the board out of the chassis.  
T1 Power Transformer, Removal and Replacement  
To remove the power transformer, the front panel assembly must first be removed to gain access to the  
bracket screws that hold the transformer in place.  
a. Remove the front panel assembly as described above.  
b. Remove the two Torx T10 screws securing the rear of the transformer bracket to the bottom of the  
chassis and the two screws securing the front of the bracket.  
c. Use long nose pliers to disconnect all wires going to the transformer terminals.  
d. Lift the transformer out of the chassis.  
NOTE:  
The AC power connections at the transformer primary are line voltage dependent. Refer  
to Figure 3-3 subsequent reconnection.  
41  
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3 - Troubleshooting  
Line Voltage Wiring  
Figure 3-3 illustrates the primary wiring configuration of the power transformer for various ac line voltages.  
Use long nose pliers to disconnect the wires going to the transformer terminals.  
NOTE:  
Install the correct fuse when changing the ac line voltage from a previous setting:  
for 110/120 Vac: 2.5AT, 250V, Agilent p/n 2110-0633;  
for 220/230 Vac: 1.25AT, 250V, Agilent p/n 2110-0788  
grey  
white/red/grey  
orange  
orange  
(spare)  
1
2
3
4
5
6
7
1
2
3
4
5
6
7
orange  
220 VAC  
120 VAC  
white/violet  
white/yellow  
white/violet  
white/yellow  
Top part of  
transformer  
Top part of  
transformer  
orange  
grey  
white/red/grey  
Front of unit  
Front of unit  
grey  
orange  
(spare)  
grey  
orange  
1
1
2
3
4
5
6
7
2
3
4
5
6
7
orange  
100 VAC  
230 VAC  
white/violet  
white/yellow  
white/violet  
white/yellow  
Top part of  
transformer  
Top part of  
transformer  
orange  
white/red/grey  
white/red/grey  
Front of unit  
Front of unit  
white/red  
red  
All Voltages  
white/red  
white/black  
white/brown  
white/black  
black  
Bottom part of  
transformer  
white/brown  
Front of unit  
Figure 3-3. Transformer Wiring  
42  
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4
Principles of Operation  
Introduction  
This section describes the different functional circuits used in the dc power supply. First, the I/O external  
signals that connect to the Agilent power supply are described. Next, the overall block diagrams for the  
dc power supply are described in detail.  
The simplified block diagrams found in Chapter 6 show the major circuits on the dc power supply as well  
as the signals between circuits. They also show the reference designations of some of the components in the  
functional circuit.  
I/O Interface Signals  
Table 4-1 describes the interface signals between the power supply and the end user (or other external  
circuits and devices).  
Table 4-1. Power Supply Interface signals  
Connector  
Signal  
Description  
Front panel outputs +OUT  
-OUT  
Positive DC output voltage  
Negative DC voltage (or return)  
Rear panel  
output/sense screw  
terminals  
+OUT  
-OUT  
+ sense  
- sense  
common  
Positive DC output voltage  
Negative DC voltage (or return)  
+OUT sensing terminal1  
-OUT sensing terminal1  
connected to ground conductor  
1Set SENSE switch to "Remote" when using the sensing  
terminals.  
INH/FLT connector  
FLT/INH mode2  
FLT output  
FLT Common  
INH Input  
Digital I/O mode  
OUT 0  
OUT 1  
IN 2/OUT 2  
Common  
pin 1  
pin 2  
pin 3  
pin 4  
INH Common  
2as-shipped configuration  
RS-232 connector  
GPIB connector  
XON-XOFF  
RTS-CTS  
DTR-DSR  
NONE  
uses ASCII control codes DC# and DC1  
uses Request-To-Send and Clear-To-Send lines  
uses Data-Terminal-Ready and Data-Set-Ready lines  
there is no flow control  
GPIB/IEEE 488  
Provides the interface to an external GPIB controller  
Can be 100 Vac, 120 Vac, 220 Vac or 240 Vac Input  
Ac input connector ac mains  
43  
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4 - Principles of Operation  
A3 Front Panel Circuits  
As shown in Figure 6-3, the supply's front panel assembly contains a circuit board, a keypad, a display, and  
a rotary control (RPG) for the output voltage and current. With the exception of the RPG (A3G1), the A3  
Front Panel board is an assembly-level replaceable part. A separate front panel binding post board is also  
included on the unit. It is also available as an assembly-level replaceable part.  
The A3 front panel board contains microprocessor circuits, which decode and execute all keypad and RPG  
commands that are transferred to the power supply output via the serial I/O port to the primary interface  
circuits on the A2 interface board. The front panel microprocessor circuits also process power supply  
measurement and status data received on the serial I/O port and send them to the display.  
A2 Interface Circuits  
The circuits on the A2 interface board provide the interface between the GPIB interface, RS-232 interface,  
and front panel interface and the dc power supply. Communication between the power supply and a GPIB  
controller is processed by the GPIB interface and the primary microprocessor circuits on the A2 board. The  
A2 Interface board is assembly-level replaceable; it contains no user-replaceable parts.  
With the exception of the front panel microprocessor, all digital circuits, analog-to-digital converters (ADC)  
and digital-to-analog converters (DAC) in the dc power supply are located on the A2 Interface board.  
Control signals between the A2 interface board and the A1 main board are either analog or level signals.  
Primary Interface  
The primary microprocessor circuits (DSP, ROM, and RAM chips) decode and execute all instructions  
and control all data transfers between the controller and the secondary interface. The primary  
microprocessor circuits also processes measurement and status data received from the secondary interface.  
A Dual Asynchronous Control chip on the A2 board converts the RS-232, RI/DFI, and front panel data into  
the primary microprocessor's 8-bit data format. The serial data is transferred between the primary interface  
and the secondary interface via a serial bus and optical isolator chips. These chips isolate the primary  
interface circuits (referenced to earth ground) from the secondary interface circuits (referenced to the  
supply’s output common).  
Secondary Interface  
The secondary interface circuits include a programmed logic array, EEPROM, boot-ROM, 8 and 12-bit  
DAC circuits, and 8 and 16-bit ADC circuits. The programmed logic array translates the serial data  
received from the primary interface into a corresponding digital signal for the appropriate DAC/ADC  
circuits. The logic array is also connected directly to four DAC/ADC circuits. Under control of the logic  
array, the selected DAC converts the data on the bus into an analog signal. Conversely, the selected ADC  
converts the analog signals from the A1 board into a digital signal.  
The logic array also directly receives status information from the A1 main board via three level-sensitive  
signal lines, which inform the array of the following operating conditions: constant voltage mode  
(CV_Detect*), constant current mode (CC_Detect*), and overvoltage (OV_Detect*). The PM_Inhibit  
control signal is used to shut down the bias voltage to the output stages and keep the power supply output  
off. The OV_SCR* control signal is used to fire the SCR and keep the power supply output off when an  
overvoltage condition has occurred.  
44  
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Principles of Operation - 4  
The EEPROM (electrically erasable programmable read-only memory) chip on the A2 interface board  
stores a variety of data and configuration information. This information includes calibration constants,  
GPIB address, present programming language, and model-dependent data, such as the minimum and  
maximum values of voltage and current. One of the EEPROM storage locations holds a checksum value  
which is used to verify the integrity of the EEPROM data. Access to the calibration data in the EEPROM is  
controlled by the combination of a password and switch settings on A2S201, located on A2 interface board  
(See Chapter 3 "Inhibit Calibration Switch").  
The Dual 12-bit DAC converts the programmed value of voltage and current on the bus into the CV_Prog  
and CC_Prog signals, which are sent to the CV control circuits in order to control the magnitude of the  
output voltage in the CV mode and output current in CC mode. The CV_Prog and CC_Prog signals are in  
the 0 to -5 V range, which corresponds to the zero to full-scale output ratings of the dc power supply.  
The Quad 8-bit DAC converts programmed information for the following circuits into analog format:  
overvoltage setting (OV_Prog), and fan speed programming (Fan_Prog). The OV_Prog signal is applied to  
the OV detect circuit, which compares the programmed overvoltage setting with the actual output voltage.  
The Fan_Prog signal is applied to the fan speed control circuit in order to speed up the fan as temperature  
increases, and to slow the fan speed down as temperature decreases.  
The 16-bit ADC in conjunction with a 4x1 multiplexer returns data from the following measurement signals  
to the logic array: monitored output voltage (VMon), monitored high-range current (Imon_H), monitored  
low-range current (Imon_L), and monitored peak current (Imon_P). All measurement signals are in the  
range of 0 to +5V, which corresponds to the zero to full-scale readback capability of the dc power supply.  
The 8-channel, 8-bit ADC returns the following signals to the logic array: high-range output current  
(Imon_H), overvoltage (V_Mon), ambient temperature (Temp_Amb), heatsink temperature (HS_Therm),  
and output fuse state (Fuse). Four of these signals are for fan control. The logic array varies the Fan_Prog  
signal depending upon the ambient temperature, the heatsink temperature, and the present output voltage  
and current. The Fuse signal informs the logic array if the output fuse (F309) is open.  
A1 Main Board Circuits  
Power Circuits  
As shown in Figures 6-2 and 6-4, the power circuits consist of: input power rectifiers and filter, primary and  
secondary bias circuits, an output regulator, a downprogrammer circuit, current-monitoring resistors, an  
overvoltage SCR, and an output filter. All bias circuits are located on the A1 PC board. Bias voltage test  
points are shown in Figure 6-1 and transformer wiring diagrams are shown in Figure 3-3.  
The primary bias circuits are referenced to chassis (earth) ground. They provide the bias for the GPIB,  
RS232 and RI/DFI interfaces, the interface micro-processor circuits and the front panel.  
The secondary bias circuits are referenced to secondary (output) common and are isolated from the chassis  
ground. They provide the bias for the amplifier and output circuits located on the A1 PC board. They also  
provide the bias for the logic array, EEPROM, DAC and ADC circuits and the secondary side of the Opto-  
isolators on A2.  
45  
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4 - Principles of Operation  
As shown in Figure 6-2, the ac input rectifier and filter converts ac input to a dc level. The output regulator  
regulates this dc level at the output of the power supply. The output regulator stage consists of two parallel  
NPN series regulators mounted on a heatsink and connected between the +Rail and the +Output. The  
conduction of these series regulators is increased or decreased by the Control signal from the CV/CC  
control circuits in order to regulate the output voltage (in CV mode), or output current (in CC mode).  
An NPN downprogramming transistor is connected between the +Output and the -Rail. The conduction of  
the downprogramming transistor is controlled by the DP_Control signal from the CV/CC control circuits.  
Whenever the output voltage is greater than the programmed voltage setting, the downprogramming  
transistor conducts and shunts current away from the load until the output voltage equals the programmed  
setting.  
The SCR, connected across the output, will fire and short the output when an overvoltage condition is  
detected. The SCR is controlled by the OV_SCR* signal from the crowbar control circuit (described in the  
next section).  
Two current shunt resistors (RmHi and RmLo) monitor the output current. RmHi monitors the high current  
range; RmLo monitors the low current range. Shunt clamps are connected in parallel across RmLo to limit  
the voltage across RmLo to about 2 volts. This corresponds to approximately 25 mA (the maximum rating  
of the low current range).  
The output filter capacitor provides additional filtering of the dc output.  
Control Circuits  
As shown in Figure 6-2, the control circuits consist of the CV/CC control, output voltage/current monitor,  
bias supplies, and SCR control.  
The CV/CC control circuits provide a CV control loop and a CC control loop. For any value of load  
resistance, the supply must act either as a constant voltage (CV) or as a constant current (CC) supply.  
Transfer between these modes is accomplished automatically by the CV/CC control circuit at a value of  
load resistance equal to the ratio of the programmed voltage value to the programmed current value. A low  
level CV_Detect* or CC_Detect* signal is returned to the secondary interface to indicate that the  
corresponding mode is in effect.  
With the CV loop in control, the output voltage is regulated by comparing the programmed voltage signal  
CV_Prog (0 to -5V) with the output voltage monitor signal VMon. The VMon signal is in the 0 to +5 V  
range, which corresponds to the zero to full-scale output voltage range of the supply. If the output voltage  
exceeds the programmed voltage, the Control signal goes low, causing the output regulator to conduct less  
and decrease the output voltage. Conversely, if the output voltage is less than the programmed voltage, the  
Control signal goes high, causing the regulator to conduct more and increase the output voltage. Depending  
upon the position of the Sense switch, the output voltage is either monitored at the supply's output terminals  
(local), or at the load (remote), using the +S and -S terminals with remote sense leads connected to the load.  
If the output voltage goes higher than the programmed value, the downprogramming stage is turned on.  
With the CC loop in control, the output current is regulated by comparing the programmed current signal  
CC_Prog (0 to -5V), with the output current monitor signal Imon_H. The Imon_H signal is produced by  
measuring the voltage drop across current monitoring resistor and is in the 0 to +3.5 V range, which  
corresponds to the zero to full-scale output current range. If the output current exceeds the programmed  
value, the Control signal goes low, causing the output regulator to conduct less and thus decrease the output  
current. Conversely, if the output current is less than the programmed value, the Control signal goes high,  
causing the output transistors to conduct more and increase the output current. A gross current limit circuit  
protects the output if the output current exceeds the maximum current rating of the unit.  
46  
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Principles of Operation - 4  
When the downprogramming stage is turned on (in either CV or CC mode), the CV/CC control circuit  
causes the Control signal to go low, which in turn causes the downprogramming transistors to conduct  
current away from the load and speed up downprogramming.  
During operation, a PM_Inhibit signal will cause the output stage bias/shutdown circuit to turn off the gated  
15 V bias voltages and shut down the output if any of the following occur:  
The output is programmed off.  
An overvoltage condition is detected (OV_Detect* signal is received).  
The line voltage falls below 90 volts (approximately).  
Current readback is provided by three separate circuits. The previously discussed high range current signal  
(Imon_H) returns the high range currrent measurement. When the unit is operating in the low current  
readback mode, a separate low range current shunt and amplifier provides low-current readback via the  
Imon_L signal . A shunt clamp (Q302 and Q304) clamps the voltage across RmLo to approximately 1.8 V.  
The third current readback circuit consists of a high bandwidth current amplifier that returns dynamic  
current measurements from the output filter capacitor via the Imon_P signal. Note that the Imon_H and the  
Imon_P signals are combined to return the actual output current measurement.  
An overvoltage detect circuit compares the output voltage to the programmed overvoltage setting. When the  
output exceeds the programmed setting, the OV_Detect* signal goes low, which informs the logic array that  
an OV condition has occurred. The crowbar control circuit is enabled when the OV_SCR* signal is  
received. When an overvoltage condition occurs, the SCR control circuit generates the OV signal, which  
causes the following actions to occur:  
1. The SCR fires, shorting the supply's output.  
2. The microprocessor circuits are notified of the OV condition (OV_Detect* is low) in order to  
program the ouput off, turn off the gated 15V bias supplies, and update the status of the unit.  
3. The PM_Inhibit signal goes high, programming the output off and shutting down the gated 15V bias  
for the output regulators.  
4. When a output protection clear command is executed, the microprocessor circuits resets the OV  
circuits, turns on the gated 15V biases, and programs the output to its previous level.  
The fan driver control circuit provides the DC voltage to operate the cooling fan. The Fan_Prog signal  
from the secondary interface circuit varies this voltage according to the ambient and heatsink temperature as  
well as the output voltage and current of the supply.  
47  
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5
Replaceable Parts List  
Introduction  
This section lists the replaceable parts for all models. Refer to Figures 5-1 and 5-2 for the  
location of mechanical parts with the reference designators MP.  
Table 5-1. Chassis, Electrical  
Designator  
A1  
Part_Number  
06611-61024  
5063-3497  
06613-61020  
06614-61020  
5063-4874  
5063-3430  
06611-60022  
5063-3434  
06632-60002  
2110-0633  
2110-0788  
2110-0699  
2110-0699  
2110-0699  
2110-0932  
2110-0685  
2110-0967  
2110-0967  
2110-0967  
2110-0932  
2110-0946  
2110-0932  
2110-0936  
2110-0936  
0960-0892  
9100-5187  
9100-5399  
9100-5186  
9100-5188  
06611-80003  
5063-3480  
Qty  
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Description  
6611C Control PCA  
A1  
6612C Control PCA  
A1  
6613C Control PCA  
A1  
6614C Control PCA  
A2  
Interface PCA  
A3  
Front Panel PCA  
A4  
Binding Post PCA  
A6  
Relay Board (Optional)  
B1  
Fan Assembly  
F301  
F301  
F303  
F305  
F306  
F308  
F309  
F309  
F309  
F309  
F310  
F311  
F311  
F311  
F311  
G1  
Fuse, 2.5AT, 250V (115Vac input)  
Fuse, 1.25AT, 250V (230Vac input)  
Fuse, sub-min, 5AM, 125V  
Fuse, sub-min, 5AM, 125V  
Fuse, sub-min, 5AM, 125V  
Fuse, smt, 5AM, 125V  
Fuse, sub-min, 7AT 125V (6611C Output Fuse)  
Fuse, sub-min, 4AT 125V (6612C Output Fuse)  
Fuse, sub-min, 4AT 125V (6613C Output Fuse)  
Fuse, sub-min, 4AT 125V (6614C Output Fuse)  
Fuse, smt, 5AM, 125V  
Fuse, smt, 10AM 125V (6611C)  
Fuse, smt, 5AM, 125V (6612C)  
Fuse, smt, 4AM 125V (6613C)  
Fuse, smt, 4AM 125V (6614C)  
Rotary pulse generator  
T1  
6611C Main Power Transformer  
6612C Main Power Transformer  
6613C Main Power Transformer  
6614C Main Power Transformer  
Primary Power Cable (E312/313 to T1)  
Secondary Power Cable (T1 to J304)  
T1  
T1  
T1  
W-1  
W-2  
49  
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5 - Replaceable Parts List  
W-3  
W-4  
W-5  
W-6  
W-7  
W-8  
W-9  
W-10  
W-11  
5063-4825  
5063-3479  
5063-3481  
5063-3478  
5080-2544  
5080-2452  
5080-2448  
06611-60056  
5080-2605  
8120-4383  
8120-1351  
8120-1369  
8120-1689  
8120-0698  
8120-2104  
8120-2956  
8120-4211  
8120-4753  
5962-8194  
5962-8198  
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
Secondary Power Cable (T1 to J306)  
Secondary Bias Cable (T1 to J305)  
Output Cable (EB315/ER315 to front panel)  
Primary Bias Cable (T1 to J303)  
Display Power/Comm Cable (A2 to A3)  
Interface Power Cable (E320/321 to A2J206)  
Interface Signal/Bias Cable (A1J307 to A2J207)  
T1 Primary Jumper  
Relay Cable (J320 to relay board) not used in 6611C  
Line Cord, (std U.S. 115Vac input)  
Line Cord, Option 900,  
Line Cord, Option 901,  
Line Cord, Option 902,  
Line Cord, Option 904,  
Line Cord, Option 906,  
Line Cord, Option 912,  
Line Cord, Option 917,  
Line Cord, Option 918,  
User’s Guide  
Programming Guide  
50  
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Replaceable Parts List - 5  
Figure 5-1. Mechanical Parts Identification  
51  
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5 - Replaceable Parts List  
Table 5-2. Chassis, Mechanical  
Designator  
MP1  
Part_Number  
5001-9873  
5063-3413  
5040-1723  
1400-0977  
1510-0091  
0590-0305  
33120-87401  
06611-40008  
06612-40003  
06613-40001  
06614-40001  
06611-40001  
06611-40002  
5001-9874  
03478-88304  
5041-8801  
0515-0433  
06611-00004  
0515-0430  
0380-0644  
2190-0586  
3050-0849  
5040-1722  
0515-2535  
0515-0374  
5080-2541  
1400-0493  
5001-0538  
0515-0383  
1252-1488  
0360-2604  
0370-2862  
1252-3056  
5001-9876  
Qty  
1
1
1
2
2
2
1
1
1
1
1
1
1
1
1
4
7
1
4
2
2
2
1
2
1
1
1
2
1
1
1
1
2
1
Description  
Chassis  
MP2  
Front Panel  
MP3  
Side Bracket, Right  
MP4  
Battery Clip  
MP5  
Binding Post  
MP6  
Hex Nut 6-32 w/Lockwasher  
Knob  
MP7  
MP8  
Window (6611C)  
MP8  
Window (6612C)  
MP8  
Window (6613C)  
MP8  
Window (6614C)  
MP9  
Pushrod (Ref Line Switch)  
Keypad  
MP10  
MP11  
MP12  
MP13  
MP14  
MP15  
MP16  
MP17  
MP18  
MP19  
MP20  
MP21  
MP22  
MP23  
MP24  
MP25  
MP26  
MP27  
MP28  
MP29  
MP30  
MP31  
Cover  
Rear Bezel  
Foot  
Screw M4x0.7x16mm, Torx T15, Pan, Conical cup  
Transformer Bracket  
Screw M3x0.5x6mm, Torx T10, Pan, Conical cup  
Stud Mounted Standoff (ref GPIB Connector)  
Helical Lock Washer, M4  
Flat Washer, #10  
Fan Spacer  
Screw M3x0.5x8mm, Torx T10, Pan Head, Thread rolling  
Screw M3x0.5x10mm, Torx T10, Pan, Conical cup  
Rear Panel Label  
Cable Tie  
Side Trim  
Screw M4x0.7x16mm, Torx T15, Pan, Conical cup  
Terminal Block, 4 Position, RI/DFI  
Terminal Block, 5 Position, Output/Sense  
Pushbutton (Ref Sense Switch)  
Screw Lock Kit (ref RS232 Connector)  
Insulator  
52  
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6
Diagrams  
Introduction  
This chapter contains drawings and diagrams for troubleshooting and maintaining the Agilent Model  
6611C, 6612C, 6613C and 6614C System DC Power Supplies.  
J320  
Conductor Side  
J307  
F310  
F308  
+5Vp  
+5Vp (unreg)  
Pri Common  
Figure 6-1. A1 Board Component and Test Point Locations  
53  
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6 - Diagrams  
Figure 6-2. A1 Board Block Diagram  
54  
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Diagrams - 6  
Figure 6-3. A2/A3 Boards Block Diagram  
55  
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6 - Diagrams  
Figure 6-4. Rail and Bias Circuits  
56  
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Index  
—+—  
—A—  
—D—  
+OUT, 43  
+sense, 43  
DAC, 44  
disable protection, 36  
disassembly - tools, 39  
disassembly procedure, 39  
downprogramming, 45, 47  
DP_Control, 45  
A1 block diagram, 54  
A1 board removal, 41  
A1 Main board, 45  
A1 test point locations, 53  
A2 board removal, 40  
A2 Interface Board, 44  
A2/A3 block diagram, 55  
A2S201, 45  
—E—  
EEPROM, 45  
electronic load, 13  
electrostatic discharge, 10  
error codes, 33  
A3 board removal, 41  
A3 Front Panel, 44  
ADC, 44  
—F—  
F309, 45  
fan speed, 36  
—B—  
Fan_Prog, 45, 47  
firmware revisions, 10, 38  
FLT, 43  
bias voltages, 34, 35  
front panel removal, 40  
Fuse, 45  
—C—  
cal denied, 37  
calibration, 37  
calibration - post repair, 37  
CC, 34  
—G—  
GPIB, 43  
CC line regulation, 19  
CC load effect, 19  
CC load regulation, 19  
CC loop, 46  
—H—  
—I—  
hazardous voltages, 9  
history, 5  
HS_Therm, 45  
CC noise, 20  
CC- operation, 18  
CC source effect, 20  
CC_Detect*, 44, 46  
CC_Prog, 45, 46  
clear password, 37  
constant current tests, 17  
constant voltage tests, 15  
Control, 45, 46  
identification, 5  
IDN? query, 38  
Imon_H, 45  
IMon_H, 46  
Imon_L, 45  
Imon_P, 45  
INH, 43  
inhibit calibration, 37  
initialization, 38  
interface signals, 43  
copyrights, 5  
cover removal, 40  
current monitoring resistor, 14  
current sink, 18  
CV, 34  
CV load effect, 15  
CV loop, 46  
CV Noise, 16  
—J—  
CV source effect, 16  
CV/CC control, 45, 46  
CV_Detect*, 44, 46  
CV_Prog, 45, 46  
J207 voltages, 35  
57  
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Index  
—M—  
—N—  
—O—  
—S—  
manual revisions, 10  
notice, 5  
safety considerations, 9  
safety summary, 3  
schematic notes, 53  
SCR, 46, 47  
secondary interface, 44  
self-test, 33  
-sense, 43  
sense switch, 46  
serial number, 5  
series regulator, 45  
shunt clamp, 46, 47  
status annunciators, 34  
-OUT, 43  
out of range, 37  
OV_Detect*, 44, 47  
OV_Prog, 45  
OV_SCR*, 44, 46  
—T—  
—P—  
Temp_Amb, 45  
test equipment, 11  
test setup, 12  
trademarks, 5  
transformer removal, 41  
PARD, 16, 20  
password, 37  
performance test form, 21  
performance tests, 14  
PM_Inhibit, 47  
transient recovery, 16  
troubleshooting - bias and reference supplies, 34, 35  
troubleshooting - equipment, 28  
troubleshooting - flowcharts, 28  
troubleshooting - introduction, 27  
troubleshooting - overall, 28  
troubleshooting - status annunciators, 34  
power-on self-test, 33  
primary interface, 44  
printing, 5  
programming, 14  
programming and output values, 14  
protection, 36  
—U—  
—R—  
UNR, 34  
rail and bias circuits, 56  
readback accuracy, 15  
reference voltages, 34, 35  
replaceable parts - chassis, 49  
revisions, 10  
—V—  
verification tests, 14  
VMon, 45, 46  
RmHi, 46  
RmLo, 46  
voltage programming, 15  
ROM upgrade, 38  
RPG, 44  
RS-232, 43  
—W—  
warranty, 2  
58  
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