LG KP260 Service Manual page 78

CHECKING FLOW
SETTING : After initialize Agilent 8960, Test GSM900, DCS, PCS mode
START
Check microphone sound hole
Make a phone call,
then check TP1 mic bias signal
comes from U103?
YES
Check the signal Level at TP2
of MIC300. Is it a few tens mV
AC?
YES
Does waveform at TP3
fluctuate?
YES
Does waveform at TP4
fluctuate?
YES
Check the soldering of
TP6
YES
Microphone will work
properly.
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Only for training and service purposes
NO
Change the U103
NO
Change the microphone
NO
Resolder component
NO
Are the TP5 LOW?
YES
Change the U301
NO
Resolder component
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4. TROUBLE SHOOTING
NO
Change the U103
LGE Internal Use Only