LG C1150 Service Manual page 74

Checking Flow
SETTING : Connect PIF to the phone, and Power on. Enter the engineering mode, and set
"Melody on" at Buzzer of BB test menu.
START
Voltage across C409
> 3.3 V?
Yes
Check the signal level of
C406,C407
Yes
The voltage
of R075 is ~2.8V
Check the state of contact of
dual mode speaker
Yes
Speaker
Working!!
No
Replace U102
( ABB LDO)
No
Replace U401
No
Check the soldering of
U402
Yes
Re-soldering
U402
No
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4. TROUBLE SHOOTING
No
Replace U402
Replace speaker