Agilent Technologies E4351B, E4350B User Manual
Addendum A - SERVICE MANUAL
Agilent Technologies Model E4350B and E4351B Solar Array Simulators - P/N 5962-8233
For units with serial numbers:
E4350B US37410101 and up
E4351B US37430101 and up
Foreword
This addendum contains information for troubleshooting and repairing the Agilent E4350B and E4351B
Solar Array Simulators. The standard Service Manual for the Agilent Series 665xA DC Power Supplies (P/N
5959-3376), together with this Service Addendum, is shipped with the Solar Array Simulators when ordered
with Option 910.
Note This addendum is to be used along with the standard Service Manual for the Agilent Series 665xA
DC Power Supplies. When troubleshooting the Agilent E4350B/E4351B Solar Array Simulators,
start by following the procedures outlined in the standard Service Manual. This addendum
documents only the differences between the standard troubleshooting procedures and the
troubleshooting procedures for a Solar Array Simulator.
Areas of Difference
From a service point of view, the main difference between the SAS unit and the Agilent Series 665xA dc
power supply is the addition of a Digital Signal Processor (DSP) board located over the main A1 board. This
DSP board includes the portions of CV, CC, OV, and OC control circuits such as the programming DAC
circuits, as well as a microprocessor and programmable gate array that is used to generate the output I-V
curve. The output I-V curve simulates the output characteristics of a solar array.
The areas in the standard service manual that are changed by this addendum are:
• Test Equipment Required (Table 2-1)
• Basic Test Setup (Figure 2-1)
• Voltage and Current Values (Table 2-3)
• CC RMS Noise Measurement Setup (Figure 2-3)
• Performance Test Record (Table 2-15)
• Self-Test Error Codes/Messages (Table 3-2)
• Troubleshooting Flowcharts (Figures 3-2, 3-5 through 3-9)
• Initialization Program Listing (Figure 3-17)
• Cable and Connector Locations (Figure 3-18)
• Disassembly Procedures for A5 DSP Board (page 3-50)
• Digital Signal Processor (DSP) Board (page 4-14)
• Simplified Power/Control/DSP Circuits (Figure 4-9)
• Parts list (Tables 5-6, 5-7, 5-9 through 5-12)
• Test Points (Table 6-3)
• Schematic Diagrams (Figures 6-5, 6-6, 6-7, 6-10, 6-11, 6-12)
S1
Service Addendum 1
Table of Contents
Addendum A - SERVICE MANUAL................................................................................................................................1
Foreword........................................................................................................................................................................1
Areas of Difference........................................................................................................................................................1
Table of Contents...........................................................................................................................................................2
Chapter 1 Differences.....................................................................................................................................................3
Chapter 2 Differences.....................................................................................................................................................3
Test Equipment Required...........................................................................................................................................3
Measurement Techniques...........................................................................................................................................4
Basic Test Setup.........................................................................................................................................................4
Voltage and Current Values.......................................................................................................................................5
Transient Recovery Time...........................................................................................................................................5
CC RMS Noise Measurement Test Setup..................................................................................................................5
Performance Test Record...........................................................................................................................................6
Chapter 3 Differences.....................................................................................................................................................8
Signature Analysis .....................................................................................................................................................8
Self-Test Error Codes/Messages................................................................................................................................8
Overall Troubleshooting (sheet 1)..............................................................................................................................9
Overall Troubleshooting (sheet 2)............................................................................................................................10
Overall Troubleshooting (sheet 3)............................................................................................................................11
Overall Troubleshooting – sheet 4...........................................................................................................................12
Overall Troubleshooting (sheet 5)...........................................................................................................................13
Flow Charts -............................................................................................................................................................13
No Display Troubleshooting....................................................................................................................................14
OV Will Not Fire Troubleshooting..........................................................................................................................15
OV at Turn-On Troubleshooting..............................................................................................................................16
Output Held Low Troubleshooting (sheet 1)...........................................................................................................17
Output Held Low Troubleshooting (sheet 2)............................................................................................................18
Output Held High Troubleshooting..........................................................................................................................19
Initialization and Factory Preset Replacement Program Listing (sheet 1) ...............................................................20
Initialization and Factory Preset Replacement Program Listing (sheet 2) ...............................................................21
Initialization and Factory Preset Replacement Program Listing – (sheet 3)............................................................22
Cable and Connector Locations ............................................................................................................................... 23
Chapter 4 Differences...................................................................................................................................................25
Digital Signal Processor (DSP) Board .....................................................................................................................25
Simplified Diagram of DSP Circuits........................................................................................................................26
Chapter 5 Differences...................................................................................................................................................27
Chapter 6 Differences...................................................................................................................................................43
Test Points................................................................................................................................................................43
Figure 6-5. A1 Main Board Component Location Coordinates for E4350B................................................................47
Figure 6-5. A1 Main Board Assembly Drawing and Test Points for E4350B.............................................................47
Figure 6-5. A1 Main Board Schematic Diagram for E4350B (sheet 1 of 4)................................................................47
Figure 6-5. A1 Main Board Schematic Diagram for E4350B (sheet 2 of 4)................................................................47
Figure 6-5. A1 Main Board Schematic Diagram for E4350B (sheet 3 of 4)................................................................47
Figure 6-5. A1 Main Board Schematic Diagram for E4350B (sheet 4 of 4)................................................................47
Figure 6-6. A4 Left Tunnel Circuit Component Loca tions for E4350B ...................................................................... 47
Figure 6-6. A4A1/A4A3 Left Tunnel Circuit Schematic Diagrams for E4350B.........................................................47
Figure 6-7. A4 Right Tunnel Circuit Component Locations for E4350B....................................................................47
Figure 6-7. A4A2/A4A4 Right Tunnel Circuit Schematic Diagrams for E4350B.......................................................47
Figure 6-10 A5 DSP Board Test Points.......................................................................................................................47
Figure 6-11 A6 Adapter Board Schematic Diagram....................................................................................................47
Figure 6-12 A7 Phone Adapter Board Component Location and Schematic Diagram................................................47
Service Addendum2
Chapter 1 Differences
Firmware Revisions
The Agilent E4350B/E4351B SAS firmware resides in the front panel board’s ROM chip (A3U4), the GPIB
board’s ROM chip (A2U106), and in the DSP board’s ROM chips (A5U734 and A5U735).
Use the *IDN query as described in chapter 3 of the Service Manual to get the firmware revision numbers.
Chapter 2 Differences
Test Equipment Required
Table 2-2. Test Equipment Required for Verification
Type Required Characteristics Recommended Model
Current Monitor Resistor 15A (0.1 Ohm) +/- 0.04% Guildline 9230/15
DC Power Supply 5V @ 10A Agilent 6642A, 6653A
Digital Voltmeter Resolution: 10 nV @ 1 V
Readout: 8 1/2 digits
Accuracy: 20 ppm
Electronic Load Voltage and current range must
exceed range of supply under test.
Power range: 500 W min.
GPIB Controller Full GPIB capabilities HP Series 300
Load Resistor
(for CC rms ripple and noise tests)
Oscilloscope Sensitivity: 1 mV
RMS Voltmeter True rms bandwidth: 20 MHz
Variable-Voltage Transformer Adjustable from -13% to +6% of
2 – 16 Ohm 300W (adjusted for 15
Ohm each connected in parallel or
series)
1 – 1.6 Ohm 300W
Bandwidth limit: 20 MHz
Probe: 1:1 with RF tip
Sensitivity: 100 uV
input range.
Power: 1 kVA min.
Agilent 3458A
Agilent 6050A mainframe with
Agilent 60504A (60 V) plug-in
module, or Agilent 60504A-J10 (120
V) plug-in module.
Ohmite E300K16R
Ohmite E300K1R6
Agilent 54504A
Agilent 3400B
Superior Electric
0 to 280 Vac, 7.5 A (226U)
0 to 140 Vac, 15 A (126U)
Service Addendum 3
Measurement Techniques
Note All tests are performed in the FIXED as shown in Figure 2-1.
• Measure the DC voltage directly at the +S and -S terminals.
• Set the SENSE switch at the back of the supply to the Remote position.
• Connect the remote sensing leads from +OUT to +S, and from -OUT to -S.
• Use adequate wire gauge for the load leads as described in Chapter 4 of the Operating Manual.
Basic Test Setup
TO OSCILLOSCOPE
OR RMS VOLTMETER
VP I P
IM-IMIP
-
+240 VDC MAX
+
-
S
+
+S-
LOCAL
REMOTE
SET TO
REMOTE
+
120 uF, 100 V
+
-
*
ELECTRONIC
LOAD
CURRENT MONITORING
RESISTOR
(GUILDLINE 0.1 OHM,
15 A, 0.04%)
* USE DC POWER SUPPLY
(SAME POLARITY CONNECTIONS)
FOR -CC TEST
Figure 2-1. Basic Test Setup
TO DVM
TO DVM OR
RMS VOLTMETER
(CC TESTS)
Service Addendum4
Voltage and Current Values
Table 2-3. Voltage and Current Values
Agilent Model Full-scale
Voltage
E4350B
E4351B
60V 61.5V 8A 8.16A 73.0V
120V 123V 4A 4.08A 140V
Max. Prog.
Voltage
Full-scale
Current
Transient Recovery Time
This test does not need to be performed on the Agilent E4350B.
CC RMS Noise Measurement Test Setup
IM-IM
-
+240 VDC MAX
-
IP
VP I P
+
-
+
+S-
S
I
Max. Prog.
Current
LOCAL
REMOTE
Max. Prog.
Overvoltage
SET TO
REMOTE
MONITOR
RESISTOR 1.6 OHM
(Adjusted to 1 Ohm +/- 1%)
LOAD RESISTOR
E4350B 2 16 Ohm resistors in parallel
(Adjusted to 7 Ohms +/- 1%)
E4351B 2 16 Ohm resistors in series
(Adjusted to 25 Ohms +/- 1%)
Figure 2-3. CC RMS Noise Measurement Test Setup
Service Addendum 5
RMS
VOLTMETER
Performance Test Record
Table 2-15A. Performance Test Record for Agilent Model E4350B
Agilent E4350B Report No.______________ Date _________________
Test Description Minimum Spec. Result * Maximum Spec. Measurement
Uncertainty
Constant Voltage Tests
Voltage Programming and
Readback Accuracy
Low Voltage (set to 0V) V
Readback Accuracy
out1
V
out1
-10mV
– 42mV
_________ mV
_________ mV
V
out1
+10mV
+ 42mV
1.5µV
2µV
High Voltage (set to 60V) V
out2
Readback Accuracy
Load Effect
Source Effect
PARD (Ripple & Noise)
Peak to Peak
RMS
Current Programming and
Readback Accuracy
Low Current (set to 0A) Iout1
Readback Accuracy
High Current (set to 8A) Iout2
Readback Accuracy
Current Sink (Isink = 1.8A)
Readback Accuracy
PARD (Ripple & Noise)
RMS
SAS Mode **
RMS
Peak to Peak
59.945V
V
– 90mV
out2
– 2mV
– 2mV
0
0
Constant Current Tests
– 20mA
I
– 28mA
out1
7.956A
I
– 30mA
out2
Isink – 48mA
0
0
0
__________ V
_________ mV
_________ mV
_________ mV
_________ mV
_________ mV
_________ mA
_________ mA
__________ A
_________ mA
_________ mA
_________ mA
_________ mA
_________ mA
60.055V
V
+ 90mV
out2
+ 2mV
+ 2mV
95mV
12mV
+20mA
+ 28mA
V
out1
8.044A
V
+ 30mA
out2
Isink + 48mA
2.4mA
4mA
32mA
845µV
845µV
40µV
40µV
840µV
2.1mV
0.5µA
20µA
3.3mA
3.3mA
1mA
1.8mA
270µA
2.6mA
Load Effect
Source Effect
– 1mA
– 1mA
_________ mA
_________ mA
+ 1mA
+ 1mA
* Enter your results in this column
** PARD (Optional Test in SAS mode)
Program I – V Curve: I
= 8A I
SC
= 7.5A V
MP
= 60V V
MP
= 65V RL = 8 Ohms.
OC
Use Fig 2-3 with scope across monitoring resistor for P-P ripple or RMS voltmeter for RMS.
Service Addendum6
3.4µA
3.4µA
Table 2-15B. Performance Test Record for Agilent Model E4351B
Agilent E4351B Report No.______________ Date _________________
Test Description Minimum Spec. Result * Maximum Spec. Measurement
Uncertainty
Constant Voltage Tests
Voltage Programming and
Readback Accuracy
Low Voltage (set to 0V) V
Readback Accuracy
out1
V
out1
-20mV
– 84mV
_________ mV
_________ mV
+20mV
V
out1
+ 84mV
1.7µV
1.7µV
High Voltage (set to 120V) V
out2
Readback Accuracy
Load Effect
Source Effect
PARD (Ripple & Noise)
Peak to Peak
RMS
Current Programming and
Readback Accuracy
Low Current (set to 0A) Iout1
Readback Accuracy
High Current (set to 4A) Iout2
Readback Accuracy
Current Sink (0.9A) Readback
Accuracy
PARD (Ripple & Noise)
RMS
SAS Mode **
RMS
Peak to Peak
119.89V
V
– 180mV
out2
– 2mV
– 2mV
0
0
Constant Current Tests
– 10mA
I
– 14mA
out1
3.982A
I
– 22mA
out2
Isink – 27mA
0
0
0
__________ V
_________ mV
_________ mV
_________ mV
_________ mV
_________ mV
_________ mA
_________ mA
__________ A
_________ mA
_________ mA
_________ mA
_________ mA
_________ mA
120.11V
V
+ 180mV
out2
+ 2mV
+ 2mV
95mV
12mV
+ 10mA
+ 14mA
V
out1
4.018A
V
+ 22mA
out2
Isink + 27mA
2.4mA
4mA
32mA
1.7mV
1.7mV
230µV
230µV
3mV
1.5mV
16µA
16µA
0.6mA
0.6mA
120µA
270µA
270µA
2.6mA
Load Effect
Source Effect
– 1mA
– 1mA
_________ mA
_________ mA
+ 1mA
+ 1mA
* Enter your results in this column
** PARD (Optional Test in SAS mode)
Program I – V Curve: I
= 4A I
SC
= 3.75A V
MP
= 120V V
MP
= 130V RL = 32 Ohms.
OC
Use Fig 2-3 with scope across monitoring resistor for P-P ripple or RMS voltmeter for RMS.
Service Addendum 7
2.2µA
2.2µA
Chapter 3 Differences
Signature Analysis
Signature analysis (SA) troubleshooting for the secondary circuits on the A1
main circuit board is ++NOT++ available for the Agilent E4350B unit. However,
GPIB and front panel signature analysis is available as described
in chapter 3 of the Service Manual.
Self-Test Error Codes/Messages
Code/Message Description Probable Cause
Table 3-2. Self-Test Error Codes/Messages
E1 FP RAM
E2 FP ROM
E3 EE CHKSUM
E4 PRI XRAM
E5 PRI IRAM
E6 PRI ROM
E7 GPIB
E8 SEC RAM
E9 SEC ROM
E10 SEC 5 V
E11 TEMP
E12 DACS
E30 SEC DAC
E31 SEC DAC
E32 SEC DAC
E45 SEC IO
E46 SEC NVRAM
Front panel RAM test failed
Front panel ROM test failed
Front panel EEPROM checksum failed
Primary interface external RAM test failed
Primary interface internal RAM test failed
Primary interface DOM test failed
GPIB interface test failed
Secondary interface RAM test failed
Secondary interface ROM test failed
Secondary interface 5 volt readback test failed
Ambient temperature readback test failed
CV or CC DAC test failed
Secondary interface DAC test failed
Secondary interface DAC test failed
Secondary interface DAC test failed
Secondary interface I/O test failed
Secondary interface nonvolatile RA M test fail ed
Microprocessor A3U3 defective
ROM A3U4 or address latch A3U8 defective
Possibly due to power loss during a write operation. See
checksum Error Recovery on page 3-3 in the Operating
manual. If power loss is not the problem, EEPROM A3U6
could be defective (after replacing U6, supply must be
initialized and calibrated).
A2 GPIB board defective
A2 GPIB board defective
A2 GPIB board defective
Talker/Listener chip A2U117 defective
A5 DSP board defective
A5 DSP board defective
A5 DSP board defective
A5 DSP board defective
A5 DSP board defective
A5 DSP board defective
A5 DSP board defective
A5 DSP board defective
A5 DSP board defective
A5 DSP board defective
Note: The following error messages can appear due to a failure occurring either while the power supply is operating or during self test.
SERIAL TIMEOUT
SERIAL DOWN
UART PARITY
UART FRAMING
UART OVERRUN
SBUF OVERRUN
SBUF FULL
STK OVERFLOW
EE WRITE ERR
SECONDARY DN
Serial data line failure on GPIB board
Serial data line failure on GPIB board
Uart failed on GPIB board
Uart failed on GPIB board
Uart failed on GPIB board
Serial buffer failure on GPIB board
Serial buffer failure on GPIB board
Stack overflow failure on DSP board
EEPROM write failure on front panel board
Serial data line failure on DSP board
A2 GPIB board defective
A2 GPIB board defective
A2 GPIB board defective
A2 GPIB board defective
A2 GPIB board defective
A2 GPIB board defective
A2 GPIB board defective
A5 DSP board defective
EEPROM A3U6 defective or calibration error
A5 DSP board defective
Service Addendum8
Overall Troubleshooting (sheet 1)
Start "Overall
Troubleshooting"
Turn off supply, disconnect
the load and push the sense
switch on the rear panel in
(local). Turn on the supply
Display On?
Yes
Fan on?
No No
Fan On?
Yes
Go to "No Display"
Troubleshooting
No
1. Check ac input and line cord
2. Check line fuse
3. Turn off supply, remove top cover, check line
voltage select jumpers on T1.
4. Tur n on supply, chec k ac power and ac bias
voltages at T1 secondary
Turn off the supply and remove top cover to access
the A1 board. Turn on the supply and check voltage
at heatsink of A1Q770 (TP 12) with respect to
common (TP 9). See Fig 6-5 Sheet 1.
Yes
Error message
displayed
?
No
Using front panel keys, program full
scale voltage and current. Check the
voltage at the supply’s output
terminals with a DMM.
Output voltage
within spec
?
Yes
Yes
See "Self Test Error
Codes/Messages",
Table 3-2
No
B
To Sheet 4
1. Check ac bias voltage at T1
secondary and cable W7. See Fig
6-2 in 665xA service manual.
A1Q700 Heatsink
+24V?
Yes
1. Check Fan B1 and cable connection to A1J601
2. Check fan speed control circuit A1Q700, A1U702
and associated components. See Fig 6-5 sheet 1.
No
2. Check A1F700, 701, D702705, C711 and R709.
A
To Sheet 2
Figure 3-2. Overall Troubleshooting (sheet 1 of 5)
Service Addendum 9
Overall Troubleshooting (sheet 2)
From Sheet 1
A
Voltage display
within spec
?
No
Reads approx. right
but outside spec
Check cables from A1
A5J722-1 (Vmon)
No
?
approx. 4.1V
?
YesYes
No
main board to A5 DSP
board.
Yes
CV
Annunciator
on ?
Yes
Turn off the supply and connect a short
across the output terminals. Turn on
and program full scale voltage and
current using front panel keys. Check
output current with an external
ammeter.
Output current
within spec?
Yes
Current display
within spec?
No
Calibrate the supply. See
Appendix A in the Operating
No
No No No
See CV/CC Status Annunciator
Troubleshooting" paragraph
C
manual.
To Sheet4
Reads approx.
right but outside
spec?
Voltage readback circuit on
A5 DSP board defective.
A5J722-3 (Imon)
approx. 4.4V
?
Check cables from A1
Main board to A5 DSP
Yes
CC Annunciator
on ?
Yes
D
To Sheet3
Yes Yes
Calibrate supply. See Appendix A in
the Operating manual.
Current readback circuit on
No
A5 DSP board defective
Current readback circuit on
A5 DSP board defective
Figure 3-2. Overall Troubleshooting (sheet 2 of 5)
Service Addendum10
Overall Troubleshooting (sheet 3)
D
From Sheet 3
Turn off the supply and remove the short from the
output. Turn on and program output voltage and
current to full scale and the OV to zero using front
panel keys. Check that the supply goes into OV
condition (OV Prot annunciator on and output at 0)
Did OV occur?
Yes
Turn off the supply and connect a GPIB
controller to the supply. Turn on the supply and
using the controller, program the supply to full
scale voltage and current. Check that the supply
accepts the commands and can be programmed
down rapidly.
Does supply accept
commands ?
Yes
Down Programming
OK
?
No
Go to "Slow Down Programming"
troubleshooting Fig. 3-15
No
No
Go to "OV Will Not Fire"
Troubleshooting
1. Check GPIB cable
2. Check A2J115, J117 and J120
Yes
Check Primary Interface A2
U113, U114, U118.
Check operation of the Digital Control Port
(See Appendix A of the Operating manual),
Serial Link (See Chapter 4 in Operating
manual) and the front panel voltage/current
rotary controls (See Chapter 5 in the Operating
No
manual).
Digital Control Port
OK
?
Yes
Check A2U109, U114.
Check Voltage and Current
controls (A3G1 & G2).
No
No
No problem found. Perform
Verification tests in Chapter 2 to
determine if a problem exists
Figure 3-2. Overall Troubleshooting (sheet 3 of 5)
Service Addendum 11
Serial Link
OK
?
Yes
Rotary Controls OK
?
Yes
Overall Troubleshooting – sheet 4
B From Sheet 1
C
From Sheet 2
Output voltage
approx. right but
outside spec
?
No
PROT
annumciator on
?
Yes
Press PROT key
Calibrate the supply. See Appendix
A in the Operating manual.
No
Display reads
approx. output
voltage
?
Yes
Display reads
approx. 0 Amps
?
Yes
Check Voltage Monitor
No
No
circuit A1U605
Output shorted
Check Current Monitor
circuit A1U605
YesYes
No
Output current
approx. right but
outside spec
?
No
Check output for
Yes
?
shorted circuits
No
Yes
Display reads
approx. output
current
?
OT
displayed
?
No
E
Output low
?
No
Go to "Output Held Low"
troubleshooting.
Yes Yes
Go to Sheet 5
Go to "Output Held Low"
Yes
A5J722-31
Therm Heatsink
3.2V @ 23C
Check +5V Ref,
A1R510,right tunnel board
A4RT301 (10K @ 23C)
Figure 3-2. Overall Troubleshooting (sheet 4 of 5)
troubleshooting.
Replace A5 DSP board
?
No
Service Addendum12
Overall Troubleshooting (sheet 5)
E From Sheet 4
Programmable OCP tripped, Check
OV & OC
displayed
?
No
Yes
OC circuits A1U405, U411, Imon
amp A1U403 and OC_PROG signal
at A5J722-26 (TP41)
OV
displayed
?
No
OC
displayed
?
No
RI (Remote Inhibit)
displayed? Check for short
between A2TB101 and
ground.
Figure 3-2. Overall Troubleshooting (sheet 5 of 5)
Yes
Yes
Go to "OV at Turn-On"
troubleshooting.
Check if OCP is enabled at turn-on
and current is programmed to zero.
Check current circuit.
Flow Charts -
The flow charts shown in Figures 3-10 through Figures 3-14 and Figure 3-16 are not used
in troubleshooting the Solar Array Simulator.
Note that there are no changes to the flow chart in Figure 3-15.
Service Addendum 13
No Display Troubleshooting
"No Display"
Start
Turn on the supply and try to program it from the
front panel. While measuring the voltage at the
output terminals, program the voltage and current to
full scale. Toggle the ON/OFF key while observing
the external voltmeter.
No display but output
OK
?
Yes
Turn off supply, remove front panel
assembly to access circuits on the A3 front
panel board. Turn on the supply.
Check 5V bias at R1-6, display voltages:
1.1V at R1-14, 2.2V at R1-2 and 3.3V at
R1-16 (meter common at R1-3). See Fig.
6-4.
Display and bias
voltages OK
?
Yes
Check 10MHz Clock signal at
A3J2-9. See Fig. 6-9.
No
Check the A2 GPIB board, bias circuits,
No
PCLR (test points 1 - 4 Table 6-3) and
cable W9
Check A3C1,
A3R1 and A3RT1.
Yes
Program voltage and current fron the front
panel. Measure the voltage at the output
terminals. In case the output is disabled
press the output ON/OFF key while
observing the output with an external
voltmeter.
Display and bias
voltages OK
?
A3U3, A3U4 or A3U8
Check A3Y1,
No
A3C3, A3C4 and
A3U3.
defective. Perform
front panel SA. See
Table 3-4.
Figure 3-5. No Display Troubleshooting
Service Addendum14
Output Voltage present
No
LCD or cable W19 defective.
?
Yes
OV Will Not Fire Troubleshooting
"OV Will Not Fire"
Start
Turn off supply and remove top cover. Turn on
and check secondary bias and reference
voltages. (Test Points 9 through 17, Table 6-3)
Voltages OK
?
Yes
Program voltage and current to full scale and
OV to 1/2 full scale. Check voltage at A5 J72222 (TP40), A1U405 and A1U602 with respect
to common (TP9).
J722-22 approx. 2.7V
?
Yes
A1U405-7 approx. 0V
?
Yes
No
Troubleshoot the appropriate
defective circuit.
Replace A5 DSP boardNo
No
Check A1R644, R747 and C417.
Voltage at A1U603-7 should be
approx. 2V.
Check voltage at A1U405-5 with
respect to common (TP9)
Yes
No
A1U405-5 Negative
?
A12U602-6 approx.
5V
?
Yes
Check voltage across A1R516
Yes
A1U602-6 approx. 5V
?
Yes
Check A1Q701 and CR700.
Check A5 J721-12. If not 5V,
No
replace A5 DSP board. If 5V
check A1U602 and DSP cable.
No
Check A1U410, Q701
(B-E short?)
Figure 3-6. OV Will Not Fire Troubleshooting
Service Addendum 15
Yes
Check A1U405.
OV at Turn-On Troubleshooting
"OV at Turn-On"
Start
Check that the supply is not programmed to OV at
turn-on. Ensure that the voltage setting is not greater
than the OV setting. Program 0V and Max. OV, then
save the settings in Register 0 (press shift, save, 0
and Enter key). Turn the supply off then back on.
Connect a DC coupled scope across the output
terminals. Turn the supply on and check that the
output does not momentarily go higher than the
voltage setting.
Momentarily goes high
Turn off the supply and remove the top cover.
Disable the OV circuit by lifting A1R447. Turn on
the supply and check the output voltage.
?
Yes
Output high
?
Yes
Caution: During
these tests, the
output may be at
hazardous levels.
Yes
Go to "Output Held High"
Troubleshooting
Yes
OV still ocurrs
?
Check voltages at A1U405-7 (TP44), U603-5 (TP17,
U405-5 (TP42) and U405-3 (TP41) to Common
(TP9). See Table 6-3.
A1U405-7 approx 5V
?
Yes
Yes
Figure 3-7. OV at Turn-on Troubleshooting
Check A1R447,
R446, C417
Check A1U411.
No
Check A1U405.
Check A1R644,
C417.
Yes
Yes
A1U405-7 approx 5V
A1U405-7 approx 5V
Replace A5 DSP board
?
No
?
No
Service Addendum16
Output Held Low Troubleshooting (sheet 1)
"Output Held Low"
Start
The supply’s output is low and the PROT
annunciator is not on. Turn supply off, disconnect
the load and remove the top cover. Turn the supply
on and check the secondary bias and reference
voltages (TP’s 9 through 12 See Table 6-3).
Voltages OK
?
Yes
Check that the +Rail and -Rail Voltages
are correct. See Fig. 6-5, Sheet 1.
Rail Voltages OK
?
Yes
Program full scale voltage and current, measure
output with an external DMM to insure the problem
is no a power supply readback problem. Check
voltages is approximately -4 volts at A5J722-15
(TP25) and A5J722-16 (TP24) with respect to
commmon (TP9).
No
No
Caution: During
these tests, the
output may be at
hazardous levels.
Troubleshoot the defective
curcuit. See Fig. 6-5 Sheet 1.
Check power xfmr T1 ac
voltages, input rectifiers and
filter caps. See Fig. 6-5 Sheet 1
Voltages OK
?
Yes
Check if CV/CC "OR" Gate diodes
A1D441 or D413 are conducting.
A1D411 Conducting
?
No
A
To Sheet 2
Figure 3-8 Output Held Low Troubleshooting (Sheet 1 of 2)
Replace A5 DSP Board
No
Check Vmon voltage at
A1U401-7 (TP33) to
common (TP9).
Yes
Yes
CV Comparator
A1U408
A1D411 Conducting
?
No
VMon Amp A1U401
defective
Service Addendum 17
Output Held Low Troubleshooting (sheet 2)
From Sheet 1
A
No
A1D413 Conducting
?
Yes
Check voltage at A1U408-3 and
R686 (TP36) to common (TP9).
A1U408-3 Neg
?
No
A1R638 > 12mV
?
Yes
Check if supply operates OK with
no load but cannot get full scale
output with load connected.
Yes
Check IMon voltage at A1U403-7
(TP28) to common (TP9).
A1D413 Conducting
?
No
IMon Amp A1U403 defective.
Gross Current Limit circuit A12U409
Yes
No
Check A1U408, D420, loading of
voltage by Tunnel Circuits.
defective.
Disconnect cables from tunnel boards
A4A1-A4A4 one at a time to see if
output rises.
Yes
CC Comparator A1U403 defective.
Partial output attained
?
No
Check Gated +9V and Shutdown
circuit. See Test Points 18-21, Table
6-3 and Figure 6-5 Sheet 2.
Figure 3-8 Output Held Low Troubleshooting (Sheet 2 of 2)
Output Rises
No
Check A1U408 and D420
Disconnect cables from Tunnel
boards one at a time to see if one has
Yes
little or no effect. Troubleshoot or
replace the defective board.
Service Addendum18
Troubleshoot or replace defective
Yes
?
tunnel board.
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