LG L602i Service Manual page 112

4.16.5 Microphone for Head_Set
MIC for Head_Set path as below:
Insert Headset -> EAR_SENSE_N(pin3) go 0V -> MSM6250A sense Head_Set insertion ->
MIC signal go to MSM
C513
33u
HPH_R
HPH_L
33u
C514
VREG_MSMP_2.7V
Try change the head set
Ear jack
VREG_MSMP_2.7V
2.2K R509
MICBIAS
22n C512
MIC2P
EAR_SENSE_N
51 R510
51 R511
STEREO_DET_N
VREG_MSMP_2.7V
HOOK_SW_N
R514 100K
Start
Make a call
OK
NO
NO
EAR_SENSE_N is 0V?
Yes
NO
MIC_BIAS is 1.8V ?
Yes
Change the Main B'd
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4. TROUBLE SHOOTING
CN501
CSS5010-9A02F
11
1
2
3
4
5
6
7
8
9
10
12
END
Check connector pin and
Head_set soldering point
Or change the Main Board
Check R509
Or change the Main Board