Audio Trouble - LG GM750 Service Manual

4. TROUBLE SHOOTING

4.10. Audio trouble

4.10.1. Receiver path
Voice Receiver path as below:
MSM7200A RCV_P, RCV_N
LGE Internal Use Only
IC501 (Audio Subsystem)
Start
Connect the phone to network
Equipment and setup call
Setup 1KHz tone out
Hear the tone to
the receiver?
NO
Change the Receiver
The sine wave appear
at R519, R531?
YES
The sine wave appear
at Speaker Solder pads?
Can you hear the tone?
YES
END
Speaker solder PAD
YES
NO
Change the Main board
NO
Check the IC501
- 124 - Copyright © 2009 LG Electronics. Inc. All right reserved.
Speaker
END
Only for training and service purposes