LG KF750 Service Manual page 121

4. TROUBLE SHOOTING
4.11.4 Headset Receiver (Voice call, Video Telephony, MP3)
START
Connect the phone to network
Equipment and setup call
Setup 1KHz tone out
Insert Headset.
Does the Headset icon display
on the main LCD?
Does the sine wave appear
3
at C613, C614 ?
Does the sine wave appear
5
at FL601 ?
Does the sine wave appear
6
at FB600, FB601?
Does the sine wave appear
7
at R816, R817?
8
Resolder CN600 Pins
or change the Headset
Can you hear sine wave
out of the receiver ?
END
LGE Internal Use Only
NO
YES
NO
Change the main B,d
YES
NO
Change the the FL601
YES
NO
Change the FB600, FB601
YES
NO
Change the FB600, FB601
YES
NO
YES
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1
Does the level of R621
under 0.5Volt ?
YES
YES
Change the main Bíd
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NO
2
Does the level of R621
over 1.6Volt ?
N0
4
Resolder R620
And try again from the start
Only for training and service purposes