Ear-Mic Hook Detection Trouble Shooting - LG KE520 Service Manual

4. TROUBLE SHOOTING

4.14 Ear-Mic Hook Detection Trouble Shooting

Disassemble the rear case of phone.
Connect the Ear-Mic Headset
to the Ear-Mic Socket of phone.
Press the HOOK Button.
Is the status of C305 LOW?
Press the HOOK Button.
Is the status of pin #1
on the U301 HIGH?
Check the soldering status
Of R302,R303,R304,C305,VA300
U103(DBB) is broken.
LGE Internal Use Only
START
YES
YES
YES
Change the board.
- 100 -
NO
Ear-Mic Headset has a
problem.
Exchange the Ear-Mic
Headset
NO
U301 has a problem.
Exchange the U301
(Comparator)
NO
Re-solder
R302,R303,R304,C305,VA300
U301
R302
R304
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Only for training and service purposes
R303