Keysight Technologies N5224A Service Manual page 87

Troubleshooting
Power Up Troubleshooting
2. If the display is dark (not visible), connect an external VGA monitor to the
rear panel Monitor output connector. (Be aware that some multisync
monitors might not be able to lock to a 60 Hz sync pulse.) If the video
information is not present on the external VGA monitor, the most probable
cause is the A21 CPU board. Refer to
CPU Board Assembly" on page
3. If the external VGA monitor displays the correct information, verify that
the front panel interface ribbon cable is properly plugged into the
motherboard connector. Refer to
Panel Assembly" on page
4. If the front panel interface ribbon cable is properly connected, suspect
that one or more of the following is defective:
— inverter board (mounted on the display assembly)
— A1 front panel interface board
— A3 display assembly
Keysight N5224A/25A Service Guide
"Removing and Replacing the A21
7-24.
"Removing and Replacing the Front
7-8.
4-15