LG -MC2670 Service Manual page 31

LG-MC2670
Circuit Flow
Check U102 Pin4
RF_IN
Check U102 Pin2
V_REG
Check U102 Pin3
DCN:Vmode (0.7v~2.1v)
Check U102 Pin5, 9, 10, 11
VCC1,2
Check U102 Pin12
RF_OUT
Waveform
U102 Pin4 DCN PAM_IN
Input Level is Appear?
YES
Vref 2.7~2.85V
OK?
YES
Level is
OK?
YES
Level is
3.4V~4.2V OK?
YES
Output Level
is Appear?
YES
PAM Circuit is OK
See next page to check
Duplexer & Mobile SW
SPECTRUM ANALYZER CONDITION
-RBW : 1MHz,VBW: 1KHz
-Span : 60MHz
-Frequency : DCN( 836.52MHz)
NO
Check F102
NO
Check Q100, U400
NO
Check U201
NO
Replace U101
NO
Replace U102
U102 Pin12 DCN PAM_OUT
28