Main Lcd Trouble - LG U990 Service Manual

4. TROUBLE SHOOTING

4.14 Main LCD trouble

Main LCD control signals are generated by MSM6280. Those signal's path are :
MSM6280 → Z ORAN (Multimedia Chip) -> 40-pin connector(CN300 in Main PCB) -> 40-pin connector
(in LCD Module)
Change the Main BD
LGE Internal Use Only
START
Press END key
to turn the power on
Is the circuit powered?
Yes
Disconnect and reconnect
40-pin B to B connector
LCD display OK?
No
Check LCD_VDD_2.8V, LCD_RESET_N,
LCD_DATA[0~15] in Main BD
No
Change the LCD module
- 142 -
No
Follow the Power ON
trouble shooting
Yes
Display OK?
No
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Yes
Yes
The LCD works
End
Only for training and service purposes