Headset Path - LG -E400 Service Manual

4.18.2 Headset path

MSM75A HPH_R, HPH_L → C714, C715(TP2) → M700 (TPA055D3: Audio Subsystem) →
R710, R711 → FB70, FB703(TP1) → CN701 ( 3.5pi Ear-jack )
Connect the phone to network
Can you hear the 1KHz TONE?
Change the U00 (MSM75A) or
LGE Internal Use Only
START
equipment and set-up call.
Set-up 1KHz tone out.
No
The sine wave appears at
FB70, FB703(TP1)?
No
The sine wave appears at
C714, C715(TP)?
No
Change the main PCB
Yes
END
Yes
Re-Solder & Change CN701 or change
the main PCB
Yes
Change the M700 (Audio Subsystem)
- 115 - Copyright © 01 LG Electronics. Inc. All right reserved.
4. TROUBLE SHOOTING
Only for training and service purposes