Mic Trouble - LG W3000 Service Manual

6) Mic. Trouble
SETTING : After Initialize Agilent 8960, Test in EGSM, DCS Mode
PIF Power On, Test after Call 112
Check if the C114 voltage is
Is the voltage at Pin 3 of
Q101 almost 0Vdc?
Check the signal level
at each side of MIC101. Is it a
of R105, R107, C120, C124,
Replace Main Board.
Reciver will work properly.
START
No
almost 2.2Vdc
Yes
No
Yes
No
few ten mVAC?
Yes
Check the soldering
No
L101, L102.
Yes
Yes
MIC Bias
voltage
No
Voltage at
pin 24 of U101 is
2.45Vdc?
Yes
Replace the R101 & R104.
Replace Q101.
Replace the Microphone,
MIC101.
Replace R105, R107, C120,
C124, L101, L102.
- 59 -
4. TROUBLE SHOOTING
Replace
the U101.