Front Panel Display Isolation - Keysight 8990B Service Manual

Front panel display isolation

Check the display cable
connection to the touchscreen
controller board and LCD
Yes
Front panel
display working?
Try with a new touchscreen
controller board
Yes
Front panel
display working?
Replace the
touchscreen
Replace the LCD
controller board
Keysight 8990B Service Guide
Front panel display trouble isolation
Connect the external monitor to
the VGA port. Turn on the 8990B.
No
Check the inverter board control cable
Check the voltage on pin 1 of J3 on
No
the touchscreen controller board. The
voltage should be 12 V.
No
Display on the
external monitor?
Yes
Front panel display
remains blank?
Yes
The voltage is 12 V?
Yes
Replace the LCD
Front panel display working?
Yes
Done
Troubleshooting Guide
No
Replace the PC motherboard
No
Replace the touchscreen
controller board
No
Replace the inverter board
3
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