LG U880 Service Manual page 117

4. TROUBLE SHOOTING
4.18.5 Microphone for Head_Set
MIC for Head_Set path as below:
Insert Headset -> EAR_SENSE_N(pin6) go 0V -> MSM6250 sense Head_Set insertion ->
MIC signal go to MSM(C200, C201) by through b-to-b connector
DAUGHTER_HEADSET
10u
R905
2.2K
R903
CN901
13
15 R907
17
1
2
3
4
5 C911
6
7
8
9
10
11
12
14
16
C915 C917
18
10p 10p
C-1827541
C914
10K
2.2K
33u
C907 33u
C931 C932
47p 47p
D901
1 6
2 5
3 4
UCLAMP0505A
Start
Make a call
Try change the head set
NO
EAR_SENSE_N is 0V?
Yes
MIC_BIAS is 1.8V ?
Yes
Change the Main B'd
VREG_MSMP_2.7V
MICBIAS
MIC2P
MIC2N
HP_OUT_L
HP_OUT_R
EAR_SENSE_N
MULTI_ADC
HOOK_SENSE_N
OK
END
NO
Change the SUB b' d
NO
Change the SUB b' d
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Near to MSM