Speaker Phone Path - LG CU400 Service Manual

4. TROUBLE SHOOTING

4.16 Speaker phone path

MSM6280 Line_R, Line_L
Audio AMP(U301)
→ connector → Speaker
Connect the phone to network
equipment and setup call
Setup 1KHz tone out
C327/R311 and C328/R312?
SPK_AMP_EN(R313) is
Sine wave appears at
Connecting speaker OK?
Can you hear the tone?
LGE Internal Use Only
Start
Sine wave appears at
YES
2.6V?
YES
SPK+
YES
YES
YES
END
- 102 -
NO
Check C327/R311 and C328/R312 or
Change the Main board
NO
Change the Main board
NO
Change the Main board
NO
Re-connect speaker
NO
Change the speaker
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