LG GX300 Service Manual page 105

4. TROUBLE SHOOTING
CHECKING FLOW
START
Set the audio part of the test
equipment to PRBS or
Continuous wave mode
Can you hear
the sound from
the earphone?
YES
Set the audio part of the test
Equipment to echo mode
Can you hear your
voice from
the earphone?
YES
Earphone will work properly
LGE Internal Use Only
NO
Change the earphone
and try again
Can you hear
YES
the sound from
the earphone?
Yes
Check the Audio signal
TP3, TP4. is it ok?
Yes
Yes
Check the Audio signal
Pin 2,3 of CN200. Is it ok?
Check the DC Voltage of
NO
pin(#4) in CN200 is about 1.2V?
YES
YES
Check the Audio signal
TP7. is it ok?
2. TROUBLE SHOOTING
NO
Check the Audio signal of
TP1, TP2. is it ok?
No
Check the signal of I2C CLK,
DATA. Is it ok?
No
No
Check the signal of I2C CLK,
DATA. Is it ok?
No
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Re download the
No
board or Replace
of U102
(BaseBand chip)
No
Re-soldering or
Replace TP5, TP6
Yes
Replace or
Change U206
Replace or
Change IC200
No
Re-soldering or
Replace TP5, TP6
Yes
Replace or
Change IC200
Only for training and service purposes