Gsm850/Egsm900 Rx - Samsung SGH-T629 Service Manual

Flow Chart of Troubleshooting
10-2.RF
10-2-1. GSM850/GSM900 RX
Continuous RX ON
RF Input : 62 CH
AMP : -50dBm
NORMAL CONDITION
Catch the channel ?
YES
CPL400 Check
Pin #1 (C414) ≥ -65dBm ?
YES
CLP400 Check
Pin #10,#11(L405) ≥ -65dBm ?
YES
U402 Check
Pin#6,#7 ≥ -65dBm ?
YES
U402 Check
Pin#1,#8,#16,#22,#31,#48
=Clean 2.8V?
YES
U402 Check
Pin#28,29,30,54=100mV?
YES
U402 Check Pin #34(R401) :
(4)
Check U402
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NO
(2)
NO
(2)
NO
(4)
NO
(4)
NO
(4)
NO
(7)
26MHz ? Vpp : 1.2V?
YES
(8)
R400 = 2.8V ?
NO
YES
(10)
TCX401
Change or resolder
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(1)
Check cable from antenna to ANT400
Check Antenna to cable contact
Check soldered status of L407, L401, C412, ANT400
(3)
C414, L402, RFS400
Resolder or Change
(2)
CLP400 Resolder or Change
(5)
Check soldered status of
L405, C428, C429
(6)
C417,C431,C449,C447,C430
Check or resolder
(7)
NO
R401 = 26MHz ?
Vpp : 1.2V?
YES
(4)
U402
Change or resolder
10-28
(9)
NO
C404,R401
resolder