LG LG-E400 - Page 121

4. TROUBLE SHOOTING
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Only for training and service purposes
LGE Internal Use Only
4.18.5 Headset micr ophone
MIC Signal: 3.5 pi Headset (CN701) → FB704 → R714 (TP4) MIC of MAX14579E & C209 (TP3) MIC2P of MSM7225A
MIC Bias : VREG_MSME_1.8V → R713 (TP1) DET → R715 DET_IN → Headset MIC
HS Detect IC Bias: VREG_P3_2.85V → C728 (TP2)
No
START
Make a call
Yes
No
Make a some sound or voice to MIC
Yes
R713(TP1) is about 1.8V?
Some sound signal appears at
R714 (TP4)?
Some sound signal appears at
C209 (TP3)?
Yes
Work Well?
END
Yes
No
Change the U200 (MSM7225A) or
Change the Main PCB
C728(TP2) is about 2.85V?
Change the U700 (MAX14579E) or
Change the Main PCB
Change the Headset or Re-solder/
Change the CN701 or
Change the Main PDB
No