Flow Chart of Troubleshooting
3-21
3-2-2. GSM900 Receiver
CONTINUOS RX ON
RF INPUT : 62CH
Cell power : -50dBm
NORMAL CONDITION
catch the channel?
CHECK
C100
NO
1
YES
F100 CHECK
pin8
≥
-65dBm?
RFS100
resolder or change
2
NO
YES
F100 CHECK
pin17,16
≥
-
65dBm?
F100
resolder or change
NO
3
U104 CHECK
pin4,5
≥
-65dBm?
YES
L105, L106, C115
resolder or change
NO
4
YES
check battery contact
NO
the power source
of U104
5
6
YES
check OSC100
and
change
U104 CHECK
Pin15,17
:13MHz
NO
YES
END
GSM Receiver is ok?
GSM RX path component
resolder or change
NO