User Guide

5-20 Flow Chart of Troubleshooting and Circuit Diagrams
5-11 GSM Receiver
Rx On
RF input : CH center freq. + 67.7 kHz
Amp. : -50 dBm
U203
Pin 8
≥ -65 dBm
U203
Pin 10
≥ -65 dBm
F203
Pin 1
≥ -70 dBm
F204
Pin 1
≥ -60 dBm
U454
Pin 53, 54
≥ -60 dBm
U454
Pin 49, 50
(225 MHz)
≥ -50 dBm
U454
Pin 43, 44
(45 MHz)
≥ -55 dBm
Resolder
CN1
Resolder &
U203 Pin 10
≥ -65 dBm
Check
VC1 : L
VC2 : L
Resolder
F203
Resolder
C234, L209, C596,
L218, C582, C758, R220
Resolder
F204, C727, L204, C600
Check
C481(CH+225MHz)
≥-20 dBm
C137(1080MHz)
≥ -20 dBm
Resolder
U478
Resolder
F200, C698, C699, C494,
C215, C213, L201, R223,
L212, L213, C242
U454
Pin 24, 25, 26, 27
≥ 40 mV
Resolder
OneC(U618), U454
Check U454
Pin 32, 33 ≥ 2.5 V
Pin 35 ≤ 0.5 V
Resolder
U454 (Pin 32,33,35)
Resolder
U618
No
No
No
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes