LG KG270 Service Manual page 75

4. TROUBLE SHOOTING
CHECKING FLOW
START
No
Does the audio
No
profile of the phone
Re-solder CN301 or Change
Check the voltage Level
change to the
another Ear- Mic set and Try again
CN301.8 = Low?
earphone mode?
Yes
Replace U100 or Change Board
Yes
Mic
Earphone
Go to MIC
Trouble section
Acoustic
Check the signal Level No
Re-solder causal
at AUX_MIC.
component
Is it about 1.2~1.5V DC
(CN301)
with a few tens mV AC?
No
Does waveform at
Replace U100 or
U102.EPPA1
Change the board
Yes
fluctuate?
Yes
Change another Ear-Mic set and Try again
Re-solder causal
No
Does waveform at component
CN301.4 and CN301.5 (CN302,C322 etc.)
fluctuate?
Change another Ear-Mic set and Try again
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