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Flow Chart of Troubleshooting and Circuit Diagrams
5-21
5-12 GSM Transmitter
Tx On (level : 5)
U401
Pin 8
≥
30 dBm
U401
Pin 5
≥
30 dBm
U402
Pin 1
≥
30 dBm
U404
Pin 1
≥
-10 dBm
U302
Pin 6
≥
-10 dBm
U302
Pin 7
≤
0.5 V
Pin 5
≥
2.8 V
Pin 3 = 0.5~2.5 V
Resolder
J401
Check
VC1 : L
VC2 : H
Change or Resolder
U401
Resolder
U402, C401
Resolder or Change
C337, R410, R413, R414, C418
Resolder
U302, R314
U301
pin 30, 47
≥
-10 dBm
Resolder
U301, U304
U301
Pin 17, 18, 19, 20
≥
40 mV
Resolder
OneC(U110)
Check U301
Pin 38
≥
2.5 V
Pin 35
≤
0.5 V
Resolder
U301 (Pin35, Pin38)
Resolder
U110
No
No
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Check
Ant. S/W Control Circuit
Check
U404 : +VBATT,
Pin 2 (APC)
OK?
Resolder or
Change U404
Yes
Check +VBATT
or APC Control
No