Power Supply Trouble Isolation - Keysight Infiniium 9000 Series Service Manual

4
Troubleshooting

Power Supply Trouble Isolation

SHOCK HAZARD!
WARNING
Only trained service personnel who are aware of the hazards involved should
perform the maintenance. Read the safety summary at the back of this book before
proceeding. Failure to observe safety precautions may result in electric shock.
For information on how to replace assemblies, see
Assemblies," starting on page 93.
These trouble isolation instructions help isolate the problem to the assembly level
when the power system is not operating. Because of advanced power system
protection features, the problem may not be with the supply itself and, therefore,
you will need to use the LEDs located in the upper right corner of the acquisition
board to determine the fault. These LEDs can be seen by looking through the rear
fan slots in the upper right corner as viewed from the rear of the oscilloscope. After
a shutdown occurs, keep the power cord plugged in so the LEDs remain
illuminated. Once you have noted the LED pattern, you can unplug the instrument.
If the oscilloscope still will not power on after you have followed the required steps
below, refer to
suggestions.
68
"Motherboard Verification"
Chapter 5, "Replacing
Look through these
slots and the fans
located behind them
to see the upper
right corner of the
acquisition board
on page 80 for additional diagnosis
Infiniium 9000 Series Oscilloscopes Service Guide