Troubleshooting Adc Adjustment Failures - Keysight Technologies E8257D Service Manual

Troubleshooting

Troubleshooting ADC Adjustment Failures

Troubleshooting ADC Adjustment Failures
The ADC adjustment adjusts the ADC reference voltage to match the A18 CPU
+10 Vdc reference. There are three reasons the adjustment could fail:
— problems with the +10 Vdc reference
— A18 CPU problems
— analog mux on another assembly is starting to fail
Procedure:
1. Run self–test 1100. If self–test 1100 passes, the +10 Vdc reference is
2. To see if an analog mux is failing and loading the supply, turn power off
3. Run the adjustment. If the adjustment passes, turn power off, reinstall one
4. If self–test fails, turn power off, reinstall the assemblies and remove the
5. Run the adjustment. If the adjustment passes, turn power off, reinstall one
6. If self–test fails, turn power off, reinstall the assemblies and remove the
7. If self–test passes, replace the A26 MID.
8. If self–test fails, replace A18 CPU.
E8257D/67D, E8663D PSG Signal Generators Service Guide
good; proceed to step 2.
and remove the A5 Sampler, A6 Frac–N, and A7 Reference.
assembly at a time and run the adjustment until the problem assembly is
located.
A8 Output, A9 YIG Driver, and A10 ALC.
assembly at a time and run the adjustment until the problem assembly is
located.
ribbon cable from J10 on the A26 MID (W35).
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