4. TROUBLE SHOOTING
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4.18.5 Headset micr ophone
MIC Signal : 3.5 pi Headset(J500)
→
FB504
→
C5(TP)
→
MICP of MSM77T
MIC Bias : VREG_GP4
→
VREG_HS_MIC_1.8V
→
R505(TP1)
→
FB504
→
Headset MIC
MIC_Bias(R505(TP1)) is about 1.8V?
No
START
Change the MSM77T or
change the main PCB
Insert Headset & make a call
Yes
The sine wave appears at
C5(TP)?
No
Make a sound (Sine wave) to MIC
Yes
Change the MSM77T or
Change the main PCB
Change the Headset or Re-solder or
change J500 or change the main PCB