Verify Lcd Backlight Functionality - Keysight n9020a 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 14, "Assembly Replacement Procedures", on page 435
manual.
2. Remove the MP7 Top Brace. Refer to
Procedures", on page 435
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
Path
in this manual.
Integrity".
60
Chapter 14, "Assembly Replacement
step 6.
"Verify Video Signal
in this