Remove The Assemblies - HP 8753E Service Manual

If the green LEDs are now on, the Al5 preregulator and A8 post regulator are
working properly and the trouble is excessive loading somewhere after the
motherboard connections at A8. Continue to "Remove the Assemblies".

Remove the Assemblies

1. Switch off the
2. Install A8. Remove the jumper from A8TP2 (AGND) to chassis ground.
Remove or disconnect all the assemblies listed below. (See Figure 5-5.)
3.
All phase lock
Switch on the analyzer and observe the green LEDs on A8.
4.
If any of the green LEDs are off or flashing, it is not likely that any of
q
the assemblies listed above is causing the problem. Continue to "Briefly
Disable the Shutdown Circuitry".
If alI green LEDs are now on, one or more of the above assemblies may be
q
faulty. Continue to next step.
Switch off the analyzer.
5.
6. Reinstall each assembly one at a time. Switch on the analyzer after each
assembly is instaIled. The assembly that causes the green LEDs to go off or
flash could be faulty.
It is possible, however, that this condition is caused by the
Note
this, reinstall the assemblies in a different order to change the
loading. If the same assembly appears to be faulty, replace that
assembly. If a different assembly appears faulty, A8 is most
likely faulty (unless both of the other assemblies are faulty).
analyzer.
Power Supply Troubleshooting 5-15