Samsung SGH-X105 Service Manual page 22

8. EGSM Reciever
CONTINUOU S RX ON
RF INPU T : 6 2CH
AM P : -50dBm
NORMAL CONDITION
catch the channel?
YES
F40 0 CHECK
pin13 ≥ -65dBm ?
YES
F40 0 CHECK
pin1 , 2 ≥ -65dBm ?
YES
U401 CHECK
pin21,2 2 ≥ -65 dBm ?
YES
U4 01
pin 12 ,13≥
-20 dBm ?
YES
U401 CHECK
pin 1 4,23,2 6,32:
clean 2.8 V?
YES
U401 pin3,4
Vp-p : 240 mV?
YES
U4 01 pin1, 2
Vp-p : 25 0mV ?
YES
U40 0 pin 2 ,3,4,5
Vp-p : 1 00mV ?
YES
NO
Check soldere d status of
R40 2
NO
CN4 00
resolder or change
NO
F4 00
resolde r or change
NO
C408 ,C41 0,L402
resolde r or change
NO
U4 03 CHECK
pin 25 ,28 : 3V ?
YES
U403 CHECK
pin 7 : 13 MHz ?
Vp-p : 8 60mV?
YES
U403 change or
resolder
NO
U1 00pin33, C11 1
check or resolder
NO
U4 00 CHECK
pin6, 20 : 2.8 V ?
YES
U40 0
resolder or change
NO
U401
resolder or change
NO
CHECK
U200
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SGH-X105 Flow Chart of Troubleshooting
NO
U10 0pin33 , C11 8
check or resolder
NO
OSC400 CHECK
pin 3 : 13 MHz ?
Vp-p : 9 50mV?
YES
C4 38,R41 6
resolder
NO
U10 0pin33 , C11 8
check or resolder
4-12
NO
NO
OSC400 CHECK
pin 4 : clean 3V ?
YES
OSC4 00 change or
resolder