Key Sense Troubleshooting - LG KU800 Service Manual

4.12 Key Sense Troubleshooting

Key Sense sequence of KU800 is :
Default condition ROW(1-4) is 2.6V → Press the key → Corresponding row(x) go to 0V → Key
sensing
Start
Check the side key
FPCB and Connector
Work well?
NO
Check the Key PCB
YES
ROW(0-4) is 2.6V?
YES
Change the Main board
Yes
End
NO
Change the Key PCB
NO
Check RA500
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4. TROUBLE SHOOTING
ROW 1
RA500
ROW 2
ROW 3
ROW 4
Side Key FPCB