Keysight Technologies Option 503 Service Manual page 60

Boot Up and Initialization Troubleshooting
Potential Problems During Boot Process
Figure 2-4 A7 Midplane Board - Test Point 518/POWER_ON_L LED
5. Turn the instrument power on from the front panel On/Off button and view
If yes:
If not:
60
the status of the POWER_ON_L LED, as shown in
Does the POWER_ON_L LED come on? (Test Point 518 should also go to
0 VDC)
Proceed to step
Verify the connection between the front panel On/Off switch and the
A4 Processor assembly by checking the status of the POWER_SW_L
control line when the front panel On/Off button is both pressed and
released. This can be monitored by measuring the voltage at Test
Point 520, as shown in
With the On/Off button released this should measure a TTL high
level, and with the button pressed it should measure a TTL low level.
The A4 Processor board assembly provides the voltage and the
switch on the front panel pulls it low when it is pressed.
6.
Figure 2-5.
N9030A PXA Signal Analyzer Service Guide
Figure 2-4.