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SGH-D428 Flow Chart of Troubleshooting and Circuit Diagrams
2-
5
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F1001 CHECK
pin13
≥
-65dBm ?
2.RF
1. EGSM RX
CONTINUOUS RX ON
RF INPUT : 62CH
AMP : -50dBm
NORMAL CONDITION
catch the channel?
CHECK
ANT1001,L1002 contact ?
U902
pin 26,32: 2.8V ?
F1001 CHECK
pin1, 2
≥
-65dBm ?
U1002 CHECK
pin20,21
≥
-65dBm ?
C1003, C1006
resolder or change
F1001
resolder or change
C1005,C1006,L1003
resolder or change
U102 pin39, C112
change or resolder
U903 CHECK
pin 7 : 13MHz ?
Vp-p : 950mV?
OSC801
change or resolder
U902
resolder or change
U702,R701
resolder or change
U902
pin1,2,5,6 Vp-p
: 120mV ?
NO
YES
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES