Table of Contents
Advertisement
5-11 GSM Receiver
RF input : CH center freq. + 67.7 kHz
Flow chart of trouble shooting and Circuit Diagram
Rx On
Amp. : -50 dBm
U304
No
Pin 2
-65 dBm
Yes
U304
Pin 9
-65 dBm
Yes
Yes
U603
No
Pin 7
-70 dBm
Yes
F303
No
Pin 2
-60 dBm
Yes
U305
No
Pin 53, 54
-60 dBm
Yes
U305
Pin 49, 50
(225 MHz)
-50 dBm
Yes
U305
Pin 43, 44
No
(45 MHz)
-55 dBm
Yes
U305
No
Pin 24, 25, 26, 27
40 mV
Yes
Check U305
No
Pin 32, 33
2.5V
Pin 35
0.5V
Yes
Resolder
U108
Check RF connector
-> resolder
Resolder &
No
U304 Pin 9
-65 dBm
Yes
Resolder
U603
Resolder
L613, L635, L639, C659
Resolder
F303, C333
L323, L324
Check
C301(CH+225MHz)
No
-20 dBm
C315(1080MHz)
-20 dBm
Resolder
U601, C309, C310, C312
C313, C314, C400, R700
Resolder
OneC(U108), U305
Resolder
U305(Pin 35, Pin 32, 33)
Check
No
VC1 : L
VC2 : L
VC3 : H
No
Resolder
U302
Yes
5-18
Advertisement
Table of Contents
