Samsung SGH-E720 Service Manual page 16

2-2.RF
2-2-1. EGSM RX
Continuous RX ON
RF Input : 62 CH
AMP : -50dBm
NORMAL CONDITION
Catch the channel ?
YES
U106 Check
Pin #9 ≥ -65dBm ?
YES
U106 Check
Pin #11 ≥ -65dBm ?
YES
F103 Check
Pin #1 ≥ -65dBm ?
YES
U103 Check
Pin#20,21 ≥ -65dBm ?
YES
U103 Check
Pin#9,32=Clean 2.8V?
YES
U103 Check
Pin#28,1,2,3=100mV?
YES
Check U401
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NO
NO
NO
NO
NO
NO
NO
U103 Check
Pin #8 : 13MHz ?
Vpp : 860mV?
YES
U103
Change or resolder
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SGH-E720 Flow Chart of Troubleshooting
Check soldered status of
R114,115,C152,109,L145
CN100,C108,L103
Resolder or Change
U106 Resolder or Change
Check soldered status of
C151,L149,V102
Resolder or Change
Check soldered status of
C120,121,L108,F103
U401,C418,100,130
Check or resolder
OSC101 Check
NO
Pin #3 : 13MHz ?
Vpp : 950mV?
YES
R112,C132
resolder
2-13
NO
OSC101 Check
Pin #4 = 2.8V ?
YES
OSC101
Change or resolder
NO