Flow Chart of Troubleshooting and Circuit Diagrams
5-20
5-12 GSM Transmitter
Tx On (level : 5)
U605
Pin 8
‡ 30 dBm
U605
Pin 5
‡ 30 dBm
U600
Pin 9
‡ 30 dBm
U600
Pin 7
‡ 0 dBm
U502
Pin 25
‡ 0 dBm
U502
Pin 5, 6, 7, 8
40 ‡ mV
Resolder
U604
Check
VC1 : L
VC2 : H
Change or Resolder
U605
Resolder
C612
Resolder
R509, R507,
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Check
Ant. S/W Control Circuit
Check
U600 : +VBATT,
Pin 2, 5, 6
OK?
Resolder or
Change U600
Yes
Check +VBATT
or PAM Control signal
No
No
Yes
Check
U502
Pin 9, 10, 12, 13
‡ -6 dBm
OK?
Resolder
U600
Check
U502
Pin 14, 23, 26, 31, 32
> 2.7 V
OK?
Yes
No
Check & Resolder
I/O signal, RF13MHz, RF PSU Part
Resolder
U502
R510, C511