Egsm Transmitter - Samsung SGH-X105 Service Manual

SGH-X105 Flow Chart of Troubleshooting

9. EGSM transmitter

NO
F40 0 pin 1 3 :
about 2~3 dBm?
YES
NO
CN400 , C40 6
check&change
C42 0 : 3.7 V?
YES
Between
R410 & U 402 :
1. 2V?
YES
NO
R407 :
≒ -5dBm ?
YES
C42 7 : 3V?
YES
U4 02
change
NO
U40 1
pin9 ,10,12 ,13
U10 0pin39,C111
:-20dBm ?
change or re solder
YES
NO
U40 1
pin5,6 ,7,8 :1.7V ?
YES
U2 00
U4 02
change
change o r resolder
NO
F4 00
pin11 : 2 .8 V?
YES
Between
C4 29&R406
≒ 4~5dBm?
YES
F400
check & change
NO
BATTERY, U1 00
check & change
NO
NO
U2 00
check
U401
pin14,2 3,26,3 2 :
2 .8V ?
YES
NO
U40 3pin5,25,2 8
: 3V ?
YES
U40 3
pin 7 : 13MHz?
Vp-p: 95 0mV
YES
U40 3
pin9 ,10,11 ,1213
: 3V?
YES
U4 01
change o r resolder
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U 200,Q20 3
check & change
NO
R4 10
check & change
YES
NO
U1 00 pin3 3,C11 8
change or re solder
NO
NO
U2 00
check or change
4-13
CONTINUS TX ON CONDITION
TX POWER DAC:500 CODE APPLIED
CH:62
RBW : 10 0KHz
VBW : 100KHz
SPAN : 10 MHz
REF LEV. : 10dBm
ATT. : 20 dB
U 200
check & change
NO
OSC400
pin 3 : 13MHz?
change o r resolder
Vp-p : 950 mV
YES
NO
0SC80 1
U1 00 pin3 3,C11 8
pin 4 : 3 V ?
change or re solder
YES
U4 03
change o r resolder
OSC40 0