Key Sense Trouble - LG U8210 Service Manual

4.13 Key Sense Trouble

Key Sense sequence of U8210 is :
Default condition ROW(0-4) is 2.6V → Press the key → Corresponding row(x) go to 0V → Key sensing
CN2
ROW[0-4]
COL[0-5]
RA1(ROW[0-4])
R4
Start
Change the side key
pcb
Work well?
NO
Check the CN2
YES
ROW(0-4) is 2.6V?
YES
Check the CN300?
NO
Change the Main board
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4. TROUBLE SHOOTING
Yes
End
NO
Change the Key pcb
NO
Check RA1 And R4
Yes
Change the Main board
CN300