Mic Trouble - LG G7100 Service Manual

4. TROUBLE SHOOTING

4.9 MIC Trouble

SETTING : After initialize Agilent 8960, Test EGSM, DCS mode
START
Check the C121
Voltage is almost
2.2V DC
Check the C147
voltage almost 1.9V,
C145 voltage a few
hundred mV
Check the R111
voltage almost 1.4V,
R112 voltage
almost 1.0V
Is the voltage at Pin 3
of Q100 almost 0V DC?
MIC Working
Checking Flow
No
Yes
No
Yes
Yes
Yes
Check the voltage at
Pin23 of U203 is
2.55V DC
Yes
Resoldering R115
Check the soldering
R113
Yes
Resoldering R113
No
No
- 84 -
No
Replace the U203
No
Replace the MIC100
Replace the Main Board
Replace Q100