Audio Trouble Shooting - LG U300 Service Manual

4. TROUBLE SHOOTING

4.17 Audio Trouble Shooting

4.17.1 Receiver Path
Voice Receiver path as below:
MSM6250A Ear1ON/Ear1OP → R623,R624 → U503(Speaker/receiver switch) → L500, L501 →
CN602(b'd to b'd connector for LCD Module) → LCD b'd to b'd connector of LCD FPCB →
LCD module → Speaker
Connect the phone to network
Equipment and setup call
Setup 1KHz tone out
Hear the tone to the receiver
Start
NO
The sine wave appear at
R623, R624?
YES
The sine wave appear at
L500, L501?
YES
The sine wave appear at
Speaker soldering point?
YES
Change the speaker
Can you hear the tone?
YES
END
- 108 -
NO
Change the Main board
NO
Check U503
Check connector pin and
NO
Speaker soldering point.
Or Change the LCD FPCB