Gsm Receiver - Samsung SGH-S300 Service Manual

2.RF

1. GSM Receiver

CONTINUOS RX ON
RF INPUT : 62CH
Cell power : -50dBm
NORMAL CONDITION
catch the channel?
YES
F 1002 CHECK
pin13 ≥ -65dBm?
YES
F 1002 CHECK
pin1,2 ≥ -65dBm?
YES
U901 CHECK
pin21,22 ≥ -65dBm?
YES
U901
pin 12,13 ≥
20dBm?
YES
U901 CHECK
pin14,23,26,32 :
3V?
YES
U901 Pin3,4
Vp-p:240mV ?
YES
U901 Pin1,2
Vp-p:250mV ?
YES
U900
Pin2,3,4,5
Vp-p:100mV ?
NO
L1006,C1015,C1019
resolder or change
SGH-S300 Flow Chart of Troubleshooting and Circuit Diagrams
NO
CHECK
C1012,L 1015,C1002 contact?
NO
CN1001
resolder or change
NO
F1002
res older or change
NO
C1007,L 1001,C1011
resolder or change
NO
U 902 CH ECK
pin5,25,28 : 3V?
YES
U902 CH ECK
pin 7 : 13M Hz?
YES
U902
change or resolder
NO
U100, PIN 46, C114
res older or change
NO
U900 CHECK
pin 6,20 : 2.8V?
YES
NO
U900
res older or change
YES
SAMSUNG Proprietary-Contents may change without notice
NO
U100, PIN 39, C116
check or res older
OSC801 CHECK
NO
pin 3 : 13MHz ?
V p-p : 950mV?
YES
C808, R805
resolder
NO
6-7
NO
OSC801 CHECK
NO
pin 4 : clean
3V?
YES
OSC801
change