get this first:
https://www.keysight.com/us/en/assets/9018-04013/service-manuals/9018-04013.pdf?success=truethen:
Chapter 1 25
Troubleshooting the Analyzer
Troubleshooting the LCD Display
Troubleshooting the LCD Display
The only adjustment that can be made to the LCD display is the viewing angle.
This is found on the front panel of the analyzer in the upper left corner.
Viewing Angle
1. Verify that the analyzer has gone through a full power-on sequence. Refer to
the section “Troubleshooting an Inoperative Analyzer” on page 21.
2. If the display is dark (not visible), connect an external VGA monitor to the rear
panel VGA output connector on the analyzer. It is possible that some multisync
monitors may 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 A4 processor assembly.
Then, use this section to TS the Processor...
Troubleshooting the A4 Processor Assembly
After you have determined that the problem is caused by the A4 processor
assembly, use the following procedures to determine if A4 must be replaced or if it
can be restored to normal operation. The ESA Spectrum Analyzer & EMC Analyzer
Component-Level Information is required to assist with some of these procedures.
Refer to Chapter 5 for a list of available component-level service information.