LG KF310 Service Manual page 75

4. TROUBLE SHOOTING
4.7.3 Loud speaker path (voice speaker phone/VT)
Loud speaker path as below:
MSM6245 SPK_R, SPK_L → C4026,C4029 → R4026,R4029 → U4002(SPEAKER AMP) →
U4001(Speaker/Receiver Selection Switch) → CN4002(Main PCB to LCD FPCB connector)
→ FPCB → OUT100, SPK PAD → Speaker
Set phone with speaker phone mode
LGE Internal Use Only
start
Connect the phone to network
Equipment and setup call
Setup 1KHz tone out
YES
The sine wave appear at
C402 6, C402 9?
YES
The sine wave appear at
FB400 0, FB400 1
YES
The sine wave appear at
VA401 4, VA401 5
YES
The sine wave appear at
FPCB SPK+, SPK-
YES
Change Speaker
- 76 -
NO
Change the
Main board
NO
Change U 4002
NO
Change U 4001
NO
Change FPCB
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