Keypad Backlight Troubleshooting - LG U830 KU830 Service Manual

4.14 Keypad Backlight Troubleshooting

Key Pad Back Light is on as below :
Key pressing → EL Driver ON → EL Sheet ON
Start
Check the side key
FPCB and Connector
Work well?
No
Check EL-Key Driver
-VPWR : C400
KEYPAD_EL_EN : R401
+VPWR( C400)
Yes
End
Yes
No
Change the Main PCB
No
Check EL Output( EL400, EL401)
No
Change the Main PCB
- 113 -
4. TROUBLE SHOOTING
Yes
Change EL Sheet
Yes
End