Flow Chart of Troubleshooting and Circuit Diagrams
5-21
5-12 GSM Transmitter
Tx On (level : 5)
U203
Pin 8
≥
30 dBm
U203
Pin 5
≥
30 dBm
U476
Pin 9
≥
30 dBm
U476
Pin 7
≥
0 dBm
U623
Pin 25
≥
0 dBm
U623
Pin 5, 6, 7, 8
40
≥
mV
Resolder
CN1
Check
VC1 : L
VC2 : H
Change or Resolder
U203
Resolder
C824, C264
Resolder
R765, C822
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Check
Ant. S/W Control Circuit
Check
U476 : +VBATT,
Pin 2, 5, 6
OK?
Resolder or
Change U476
Yes
Check +VBATT
or PAM Control signal
No
No
Yes
Check
U623
Pin 9, 10, 12, 13
≥
-6 dBm
OK?
Resolder
U467
Check
U623
Pin 14, 23, 26, 31, 32
> 2.7 V
OK?
Yes
No
Check & Resolder
I/O signal, RF13MHz, RF PSU Part
Resolder
U623