LG G3100 Service Manual page 86

4. TROUBLE SHOOTING
The signal flow of
the microphone to
U103.
MIC activating signal : Mic is
activated when this signal
goes to high.
R206, R208,
C208, C211
- 88 -
C204
R202
R204
The voltage at pin. 3 of
Q203 goes to almost 0V
when the mic is activated.