Improper Lcd Display - Panasonic UF-5500 Service Manual

11.1.2. Improper LCD Display

START
Check connectors: CN511
(MAIN PCB) and CN2
(OPERATION PCB).
When pressing any key,
do you hear the 'Pi-' sound from
the Speaker?
Replace the OPERATION PCB.
1
No
Does CN511, pin 6 and
Yes pin 7 on the MAIN PCB
measure +5VDC?
Reinstall the firmware.
END
No
Yes
Replace the MAIN PCB.
125
UF-5500 / 4500