Headset Path - LG KS20 Operating Instructions Manual

4. TROUBLE SHOOTING

4.18 Headset path

MSM7200 HPH_R, HPH_L → C409, C406 → HEADSET AMP(U402) → R405, R404 → FB301,
FB300 → CN300 (MMI Connector)→
Connect the phone to network
equipment and setup call.
Setup 1KHz tone out
and insert headset.
Check an U100 SMT status
Exchange U100 or
Change the Main board
And Retest
LGE Internal Use Only
Start
Can you hear the tone?
NO
Sine wave appears at
FB301/FB300?
NO
by X-ray
YES
END
YES
Change the Headset
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Only for training and service purposes