LG KU950 Service Manual page 126

4.17.5. Microphone for headset
MIC for Head_Set path as below:
Insert Headset → EAR_SENSE_N(pin8) go 0V → MSM6275A sense Head_Set insertion →
MIC signal go to MSM(C304).
MMI 18Pin CONNECTOR
CN601
21
19
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
20
22
Try change the head set
EAR_SENSE_N is 0V?
MIC_BIAS is 1.8V ?
Change the Main B'd
VREG_MSMP_2.7V
EAR_MIC_P
MIDI_EAR_L
MIDI_EAR_R
RMT_INT/USB_D+
RMT_ADC/USB_D-
EAR_SENSE_N
VBATT
FL600
REMOTE_PWR_ON
1 2
IN OUT +5V_PWR
3 4
G1 G2
USB_VBUS
NFM21PC105B1A3
UART_TXD
R626 0
UART_RXD
R627 0
R629 NA
TCC_UART_TXD
R630 NA
TCC_UART_RXD
Start
Make a call
OK
NO
NO
Yes
NO
Yes
- 127 -
4. TROUBLE SHOOTING
C300
10p
MDP_VSYNC_SECONDA_GPIO104
MDP_VSYNC_PRIMARY_GPIO105
END
Change the Main b'd
Change the Main b'd
C307 C308 C309
NA NA NA
C314
0.1u
Near to MSM
F25
SDCC_DAT1_GPIO99
M25
SDCC_DAT2_GPIO100
M26
SDCC_DAT3_GPIO101
AE3
AD2 R315 NA