SAMSUNG Proprietary-Contents may change without notice
5-11
SGH-A408 Flow Chart of Troubleshooting and Circuit Diagram
5-11. GSM Receiver
RX On
RF input : 62 CH
Amp. : -50 dBm
Y
N
N
Y
U505
Pin 9
≥
-65 dBm
Resolder or Change CN500
Y
F501
pin 5
≥
-73 dBm
Resolder
F501
N
Y
F300
pin 4
≥
-30 dBm
Change
F300
N
Y
Check the
signal at U300
pin 26, 27
Change
U300
N
Y
U505
Pin 5
≥
-65 dBm
N
Y
Resolder& U505
Pin 5
≥
-65 dBm
Check voltage
U505 pins
Pin 2 : L
Pin 4 : H
Pin 8 : H
Pin 10 : L
N
Y
U507
pin 16, 17
≥
-40 dBm
Y
Check OSC300
pin 1
≥
-10 dBm
Change OSC300
Change U507
Y
Change U300
END
N
N
Y
F301
pin 1, 2, 5, 6
≥
-47 dBm
Change F301
N
Y
F300
pin 1
≥
-25 dBm
Check D300
pin 1
≥
1V~2.3V
Resolder or change
D300
N
1
2
3
4
5
6
7
8