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Troubleshooting
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Troubleshooting Hints
1. Read all troubleshooting instructions before attempting to troubleshoot the unit.
2. If the AC Power Source operates properly but does not deliver full output power capability, check the ac input mains
fuses located on the rear panel.
3. The amplifiers, ( Al, A2, A3 ) may be interchanged in identical models for troubleshooting purposes. The Agilent
6814A, 6834A, and 6843A models Al, A2, A3 amplifiers cannot be used in the Agilent 6814B or 6834B models. See
Chapter 5, Replaceable Parts, for correct replacement amplifier.
4. The Agilent 6814B uses amplifiers Al and A2 and the 6843A uses amplifiers A1, A2 and A3 connected in parallel at
the output. Drawings show the connections and schematics for the Agilent 6834B 3 phase unit. When troubleshooting
the Agilent 6814B, the A3 amplifier and its associated parts are deleted from specific circuit boards.
5. Troubleshooting the A9 option 400 ( 380 to 460 volt ) Input PS is not recommended at this time. This is a 500 Vdc to
300 Vdc step down switching regulator and contains hazardous voltages.
Switching Amplifier Output Balance Adjustments
If the switching amplifiers ( A1, A2 or A3 ) are replaced phase B and C amplifier gains may require adjustment so they
better match that of phase A and current share equally when paralleled as a single phase output.
6834B Amplifier Balancing
1. With ACS off, temporarily short A5TP1 to A5TP2 on the A5 Relay board (this deactivates the paralleling relays).
2. Turn on ACS, program the output for single-phase operation, 300V, 60Hz, no load.
3. Measure the voltage from phase A output to common and from phase B output to common.
4. Adjust the phase B gain pot, A2A2R104, until phase B output matches phase A output to within 50 millivolts.
5. Measure the phase C output to common.
6. Adjust the phase C gain pot , A3A2R104, until phase C output matches phase A output to within 50 millivolts.
7. Turn off ACS and remove the short from TP1 to TP2.
6814B Amplifier Balancing
1. Turn off ACS, remove phase B amplifier. Turn on ACS. Program output voltage to 300V, 60Hz, no load.
2. Measure and note drive voltage on A6 Servo board at A6TP5 with respect to A6TP1.
3. Turn off ACS, remove phase A amplifier, install phase B amplifier in phase B slot. Turn on ACS. Program output
voltage to 300V, 60Hz, no load.
4. Measure drive voltage at A6TP3 as before. Adjust phase B gain pot A2A2R104 for same drive voltage as noted in step
2, plus or minus 2 millivolts.
5. Turn off ACS, re-install phase A amplifier in phase A slot.
6843A Amplifier Balancing
1. Turn off ACS, remove phase B and C amplifiers. Turn on ACS. Program output voltage to 300V, 60Hz, no load.
2. Measure and note drive voltage on A6 Servo board at A6TP3 with respect to A6TP1.
3. Turn off ACS, remove phase A amplifier, install phase B amplifier in phase B slot. Turn on ACS. Program output
voltage to 300V, 60Hz, no load.
4. Measure drive voltage at A6TP3 as before. Adjust phase B gain pot A2A2R104 for same drive voltage as noted in step
2, plus or minus 2 millivolts.
5. Turn off ACS, remove phase B amplifier, install phase C amplifier in phase C slot. Turn on ACS. Program output
voltage for 300V, 60Hz, no load.
6. Measure drive voltage at A6TP3 as before. Adjust phase C gain pot A3A2R104 for same drive voltage as noted in
step 2, plus or minus 2 millivolts.
7. Turn off ACS, re-install phase A and phase B amplifiers in their respective slots.