LG KG70c Service Manual page 35

KG70C
Circuit Flow Circuit Flow
Check U104 Pin#2 Check U104 Pin#2
Check U104 Pin#4 Check U104 Pin#4
Check U102 Pin#2 Check U102 Pin#2
Check U104 Pin #1, 8 Check U104 Pin #1, 8
Check U104 Pin# 7 Check U104 Pin# 7
Waveform Waveform
U104 Pin#2 RF_ IN U104 Pin#2 RF_ IN
Graph 3-2-4(a) Graph 3-2-4(a)
NO NO
Input Level is Appear? Input Level is Appear?
YES YES
NO NO
Vreg 2.6~2.8V Vreg 2.6~2.8V
OK? OK?
YES YES
NO NO
Level is Level is
3.2V~4.2V OK? 3.2V~4.2V OK?
YES YES
NO NO
Level is Level is
3.2V~4.2V OK? 3.2V~4.2V OK?
YES YES
NO NO
Output Level Output Level
is Appear? is Appear?
YES YES
PAM Circuit is OK PAM Circuit is OK
See next page to check See next page to check
Duplexer & M obile SW Duplexer & M obile SW
34
Check F100 Check F100
Check Q100,U400 Check Q100,U400
Check U102 Check U102
Replace U104 Replace U104
Replace U104 Replace U104
U104 Pin#7 RF_ OUT U104 Pin#7 RF_ OUT
Graph 3-2-4(b) Graph 3-2-4(b)