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Only for training and service purposes
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4. TROUBLE SHOOTING
START
NO
YES
Microphone will work
properly.
SETTING : After initialize Agilent 8960, Test GSM900, DCS mode
YES
Check the signal Level at TP2 of
MIC300. Is it a few tens mV AC?
Check the soldering of
TP6
Make a phone call,
then check TP1 mic bias signal
comes from U103?
NO
Change the microphone
YES
NO
Resolder component
CHECKING FLOW
Change the U103
Check microphone sound hole
Does waveform at TP3
fluctuate?
NO
Resolder component
YES
Does waveform at TP4
fluctuate?
NO
Are the TP5 LOW?
NO
Change the U103
YES
Change the U300
YES