4-12 Service Guide N5242-90001
Troubleshooting PNA Series Microwave Network Analyzers
Power Up Troubleshooting N5242A
3. If the correct voltage is present at each connection and the fan connectors are in good
mechanical condition, suspect a defective fan. Refer to “Removing and Replacing the
Fans” on page 7-60.
If the correct voltage is not present, suspect a defective A14 system motherboard. Refer
to “Removing and Replacing the A14 System Motherboard” on page 7-16.
Troubleshooting LCD Display Problems
This procedure is intended to isolate the faulty assembly when the display is dark. If the
display is lit, but the color mix is faulty, refer to “A3 Display Test” on page 4-15.
NOTE
There are no front panel adjustments for intensity and contrast of the LCD.
1. If the display is dim, the A3 display assembly is defective. Refer to “Removing and
Replacing the A1–A3 and Other Front Panel Subassemblies” on page 7-10.
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 A17 CPU board. Refer to “Removing and
Replacing the A17 CPU Board Assembly” on page 7-22.
2. 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
“Removing and Replacing the Front Panel Assembly” on page 7-8.
3. 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
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