Verify Lcd Backlight Functionality - Keysight N9000A Service Manual

Boot Up and Initialization Troubleshooting
Potential Problems During Boot Process

Verify LCD Backlight Functionality

There are two backlights within the LCD assembly, one across the top and one
across the bottom. If only one of the backlights has burnt out, the other will still
function. Considering this fact, as well as the fact that the expected life span of the
backlights is much longer than the LCD itself, it is not very likely that the
backlights themselves would cause a completely blank display.
To determine if a blank display problem is backlight related:
1. Remove the AC power cord and then remove the instrument cover. Refer to
Chapter 13, "Assembly Replacement Procedures," on page 225
2. Remove the MP7 Top Brace. Refer to
Procedures," on page 225
3. Turn the instrument on and allow enough time for it to completely boot-up.
4. Shine a bright light at the display and look closely for the expected information
(a large flashlight should work). Since most of the display section of the screen
has a black background you will need to look at either the area next to the
softkeys or the area across the top of the screen, since these sections will have
the largest areas of lighter information in them.
5. Can the expected display information now be seen?
If yes:
The problem is backlight related. Proceed to
If no:
The problem is not backlight related. Skip to
Integrity".
58
Chapter 13, "Assembly Replacement
in this manual.
step
"Verify Video Signal Path
in this manual.
6.
Chapter 2