LG KG290 - Page 84

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4. TROUBLE SHOOTING
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Does the audio
profile of the phone
change to the
earphone mode?
NO
YES
Resolder CN300
YES
Earphone will work properly
Change earphone
Level at pin3
of U302 is high
NO
Can you hear your
voice from
the earphone?
Set the audio part of the test
Equipment to echo mode
Change the earphone
and try again
NO
Can you hear your
voice from
the earphone?
YES
Can you hear
the sound from
the earphone?
NO
Set the audio part of
the test equipment to
PRBS or continuous
wave mode
Download software.
YES
Does it work well?
Change the main board.
YES
NO
Voltage at
U301.5 is
High ?
Voltage at
U300.1 is
Low ?
YES
Earphone will work properly
If not, check the U300, U301
YES
Download software
Resolder component
Replace U302
YES
NO
NO
CHECKING FLOW