LG LG-E400 - Audio Troble

4. TROUBLE SHOOTING
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Only for training and service purposes
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4.18 Audio Troble
4.18.1 Receiver Path
MSM7225A EAR1_OP, EAR1_ON → RCV_P, RCV_N → R702, R703 (TP3) →
M700 (TPA2055D3: Audio Subsystem) → FB705, FB706 (TP2) → CN700 (TP1) (Antenna + SPK pad)
Yes
No
START
END
Yes
No
Connect the phone to network
equipment and set-up call.
Set-up 1KHz tone out.
No
Yes
Re-contact or Change the SPK/RCV
module
No
Change the SPK/RCV module
Change the M700 (Audio Subsystem)
Yes
Change the U200 (MSM7225A) or
Change the main PCB
Can you hear the 1KHz TONE?
The sine wave appears at
CN700 (TP1) ?
The sine wave appears at
FB705, FB706 (TP2)?
The sine wave appears at
R702, R703(TP3)?