LG T5100, Service Manual, Page: 52 / 136

3. BASEBAND PART TROUBLE SHOOTING
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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
No
Yes
Go to Earphone
Detect Problem
Make a call and insert the earphone
into headset
Does the audio profile change
to the earphone mode?
Can you hear the sound
from the earphone ?
Set the menu of test equipment
to PBRS or continuous wave mode
Does sine-wave appear
at C108?
Does sine-wave appear
at TP303,304 ?
Does sine-wave appear
at C337, C338 ?
The soldering of J1 is OK?
Yes
Go to
Sending Path Problem
No
No
ABB is out of order
Change the Board
Yes
U301 is out of order
Change the Board
Yes
No
U707 is out of order
Change the Board
No
Yes
No
Change the Ear-Jack J1
Change the Earphone
Does sine-wave appear
at L501, L502 ?
Resolder CN3 and
Reconnect B-to-B Conn.
No
Yes
Yes