LG T5100 Service Manual page 52

Earphone Detecting Operation
- The ABB operates A/D conversion continuously and if the voltage of "ADIN4" node goes below
1.3V, it detects earphone insertion.
- The ABB operates A/D conversion continuously and if the voltage of "ADIN4" node goes below
0.4V, it detects hook-switch of earphone is pushed.
Earphone Sending Path
- HSMICP is the audio input signal from the microphone of earphone.
- L500, R332 make the path of the audio signal from the microphone of the earphone.
Earphone Receiving Path
- HSO is the mono-type audio output signal to receiver of earphone.
- This signal delivered to U301(external audio codec) and it makes stereo-type audio output signal.
- This stereo-type output is delivered to the receiver through U707(analog switch IC).
START
Does the audio profile change
to the earphone mode?
Yes
Can you hear the sound
from the earphone ?
No
Does sine-wave appear
at C108?
Yes
Does sine-wave appear
at TP303,304 ?
Yes
Does sine-wave appear
at C337, C338 ?
Yes
Does sine-wave appear
at L501, L502 ?
Yes
The soldering of J1 is OK?
Yes
Change the Earphone
Make a call and insert the earphone
into headset
No
Go to Earphone
Detect Problem
Set the menu of test equipment
to PBRS or continuous wave mode
Yes
Sending Path Problem
No
ABB is out of order
Change the Board
No
U301 is out of order
Change the Board
No
U707 is out of order
Change the Board
No
Resolder CN3 and
Reconnect B-to-B Conn.
No
Change the Ear-Jack J1
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3. BASEBAND PART TROUBLE SHOOTING
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