Samsung SGH-S300 Service Manual page 27

SGH-S300 Flow Chart of Troubleshooting and Circuit Diagrams
4. GSM Transmitter
F1002 pin 13
about 2~3dBm?
YES
CN1001, C1012
check & change
pin 4 : 3.7 V?
pin 2 : 1.2 V
Vand pin3:3V
U1001 pin 7
change & resolder
U100 pin46,C114 U901
change or
pin9,10,12,13:
resolder -20dBm?
U901
NO
pin5,6,7,8
U700 U1001
change check & change
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NO
F1002
pin 11 : 2.8V
YES
U1001 pin 9
pin 3~4dBm?
NO
YES
F1002
check & change
NO
U1001
BATTERY, U100
check & change
YES
NO
U1001
YES
NO
U1001pin2:0
U700
check & change
YES
NO
U1001pin 6:
1.2 V?
YES
NO
: -5dBm?
YES
U1001
U901
NO
pin14,23,26,32
2.8V?
YES
U901
NO
pin5,25,28
3V?
YES
U902
pin 7 13MHz
Vp-p :950mV
1.7V
YES
U902
pin9,10,11,13
3V?
U901
change or
res older
SAMSUNG Proprietary-Contents may change without notice
NO
U700,U701
check & change
U100 pin39,c116
NO
change or
res older
YES
NO
YES
NO
U700
check & change
YES
6-10
CONTINUS TX ON
CONDITION
MS TX level 19
CH : 62
RBW : 100KHz
VBW : 100KHz
SPAN : 10MH z
REF LEV. : 10dBm
ATT. : 20dB
OSC801
OSC801
NO
pin 3 :13MHz?
change or
Vp-p : 950mV
resolder
YES
U100 pin39,c116
NO
OSC801
change or
pin 4 : 3V ?
resolder
YES
U902
change or
res older