LG KD3500 Service Manual page 32

Circuit Flow
Check U102 Pin2
RF_IN
Check U102 Pin4
V_ref
Check U102 Pin1,8
VCC1,2
Check U102 Pin7
RF_OUT
Waveform
U102 Pin2 DCN PAM_IN
NO
Input Level is Appear?
YES
NO
Is Vref 2.85V ?
YES
NO
Level is
3.2V~4.2V OK?
YES
NO
Output Level
is Appear?
YES
PAM Circuit is OK
See next page to check
Duplexer & Mobile SW
Or Replace QSC6010
Check F110 circuit
Check Q101 circuit
Check C203, U201
Replace U102
U102 Pin7 DCN PAM_OUT