LG U880 Service Manual page 111

4. TROUBLE SHOOTING
4.18.2 Voice and Sound Path for Head_set
Voice and Multimedia Sound path for Head_Set as below:
MSM6250 HPH_R, HPH_L -> CN500 pin 17,18 for SUB b;d -> C907,C911 in SUB b'd ->
CN901 headset Jack pin 4,5 in SUB b'd
Start
Connect the phone to network
Equipment and setup call
Setup 1KHz tone out
And insert head_Set
Headset insertion detection
in the Main LCD Display OK?
YES
The sine wave appear at
CN500 pin 17,18 ?
YES
The sine wave appear at
C907,C911 in SUB b' d?
YES
Can you hear the tone?
YES
END
NO
Check CN901 pin 6 or
Change the SUB b' d
NO
Change the Main board
NO
Check the connector pin
or change the SUB b' d
NO
Check the CN901
or change the SUB b' d
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