Gsm900 Transmitter - Samsung SGH-E390 Service Manual

Flow Chart of Troubleshooting

9-13. GSM900 Transmitter

TX ON (5Level)
Yes
F100 Pin10
>= 20dBm
No
F100 pin15
>= 18dBm
No
U100 pin12
>= 18dBm
No
U100 pin7
>= -11dBm
No
U102 pin36
>= -15dBm
No
U102 pin 1,2,3,4
>= 1V
No
Check UCP200
END
Yes
Resolder RFS100,C101,L100
Yes
Yes
Resolder C111,L108.C114
Yes
Yes
Yes
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Check F100
pin14 = H (2.68V)
pin13 = L
No
Yes
Check U100
pin 2,3,4,5,6 OK?
No
Resolder L112
Check U102
Yes
pin5,8,19,31,35,39
>=2.7V
No
9-24
Yes
Change or Resolder F100
Check ANT Switch
control circuit
Resolder or Change U100
Check +VBAT or PAM
control signal
Resolder U102
Check & Resolder RFLO
signal, RF26MHz,
RF PSU Part