LG -E400f Service Manual page 99

4.18.3 Speaker/Speaker Phone path
MSM75A LINE_OP, LINE_ON → C716, C718(TP3) → M700(TPA055D3 : Audio Subsystem) → FB705, FB706(TP2) →
CN700(TP1)(Antenna + SPK pad)
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
CN700 (TP1)
No
The Sine wave appears at
FB705, FB706(TP)?
No
The Sine wave appears at
C716, C718(TP3)?
No
Change the main PCB
Yes
END
Yes
Re-contact or Change the SPK/RCV module
Yes
Change the SPK/RCV module
Yes
Change the M700 (Audio Subsystem)
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4. TROUBLE SHOOTING
Only for training and service purposes