Service manual

4. TROUBLE SHOOTING
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Copyright © 2012 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
4.19 Audio Troble
4.19.1 Receiver Path
MSM7227A-1-AA RCV_N / RCV_P -> CN900 (TP1) (RCV pad)
Yes
No
START
END
Connect the phone to network
equipment and set-up call.
Set-up 1KHz tone out.
No
Yes
Re-solder or test the new RCV. (If it’s OK,
Change the RCV.)
No
Change the FPCB
Yes
Change the U200 (MSM7227A-1-AA) or
Change the main PCB.
Can you hear the 1KHz TONE?
The sine wave appears at
CN900 (TP1) ?
Re-contact or test the new
Upper FPCB.