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5-12 GSM Receiver
RF input : CH center freq. + 67.7 kHz
Flow chart of Troubleshooting and Circuit Diagram
Rx On
Amp. : -50 dBm
U706
No
Pin 8
°√ -65 dBm
Yes
U706
No
Pin 10
°√ -65 dBm
Yes
F602
No
Pin 7
°√ -70 dBm
Yes
F601
No
Pin 1
°√ -60 dBm
Yes
U601
No
Pin 53, 54
°√ -60 dBm
Yes
U601
No
Pin 49, 50
(225 MHz)
°√ -50 dBm
Yes
U601
No
Pin 43, 44
(45 MHz)
°√ -55 dBm
Yes
U601
No
Pin 24, 25, 26, 27
°√ 40 mV
Yes
Check U601
No
Pin 32, 33 °√ 2.5 V
Pin 35 °√ 0.5 V
Yes
Resolder
U400
Check RF connector
-> resolder
Resolder &
U706 Pin 10
°√ -65 dBm
Yes
Resolder
F602
Resolder
C621, L602, L610, C629
Resolder
F601, C610, L603
Check
C504(CH+225MHz)
°√-20 dBm
C510(1080MHz)
°√ -20 dBm
Yes
Resolder
F604,C607,C611,C608
C613,C605,C609,R601
Resolder
OneC(U400), U601
Resolder
U601 (Pin35, Pin 32, 33)
Check
No
VC1 : L
VC2 : L
No
Resolder
U501
5-19
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