User Guide

Flow chart of trouble shooting and Circuit Diagram 5-18
5-11 GSM Receiver
Rx On
RF input : CH center freq. + 67.7 kHz
Amp. : -50 dBm
U304
Pin 2
≥ -65 dBm
U304
Pin 9
≥ -65 dBm
U603
Pin 7
≥ -70 dBm
F303
Pin 2
≥ -60 dBm
U305
Pin 53, 54
≥ -60 dBm
U305
Pin 49, 50
(225 MHz)
≥ -50 dBm
U305
Pin 43, 44
(45 MHz)
≥ -55 dBm
Check RF connector
-> resolder
Resolder &
U304 Pin 9
≥ -65 dBm
Check
VC1 : L
VC2 : L
VC3 : H
Resolder
U603
Resolder
L613, L635, L639, C695
Resolder
F303, C333
L323, L324
Check
C301(CH+225MHz)
≥ -20 dBm
C315(1080MHz)
≥ -20 dBm
Resolder
U302
Resolder
U601,C309,C310,C312
C313,C314,C400,R700
U305
Pin 24, 25, 26, 27
≥ 40 mV
Resolder
OneC(U108), U305
Check U305
Pin 32, 33 ≥ 2.5 V
Pin 35 ≥ 0.5 V
Resolder
U305 (Pin35, Pin 32, 33)
Resolder
U108
No
No
No
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes