Samsung SGH-A500 Service Manual page 21

9. GSM Reciever
<Test Condition>
1. Phone Tool Inline Mode :
- RF Mode : Rx Continuous.
- ARFCN : Rx 62Ch.
- Gain : Rx 88.
2. Generator RF Level :-50dBm.
3. Measure with Hewlett Packard 85024A active high frequency probe.
→ Measured Value is dependent on Probe Measured Point of Component.
●Flow Chart.(GSM : Rx Trouble Shooting)
Check RF(947.4MH z)
Level at C112
>-55dBm
Yes
Check RF
Level at C229
> -57dBm
Yes
Check RF Level
both side at C302
> -60dBm and
Almost Same Level
Yes
Check IF(360MH z)
L evel at C229 >
-30dBm
Yes
Check IF(360M Hz)
Level Both Side at
L209 > -40dBm and
Almost Same Level
Check the Baseband
Level(Vpp : 1V) at 8,
9 , 10, 11pin of
U201
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SGH-A500 Flow Chart of Troubleshooting and Circuit Diagrams
No
Replace or Resolder the CON101 &
Check the Crack
No
& Soldering of
U101
Resolder or Replace the
U101
No
Resolder or Replace C302, L 207, L208,
No
Level(>-5dBm) and
RF_Out of OSC201
Level(>0.6Vpp) and
Frequency(13MHz)
No
Res older or Replace the F204, L 204, C228,
Yes
No
SAMSUNG Proprietary-Contents may change without notice
C112
Check 0 ~ 0.5 V
at 2 pin, 10pin of
OK
U101
No
Resolder the U105,
U104
F202
Check the Pin connection(VRF1) Between
7, 19, 26, 30, 38, 39 pin of U201 and 31
Check the
No
Frequency
(1307.4MHz)
Having Some Defect at B'd → Need To send
Yes
Check
No
of OSC202
Resolder or Replace the OSC202, R226,
C234, L218
Check the 2nd Local
No
Frequency(1440MHz)
on beside the 38 pin
of U202
6-7
No
pin of U601.
No
Check Voltage at
7, 19, 26, 30, 38,
39 pin of U201(2.6
~ 2. 9V)
to Korea
No
Check Voltage(2.6 ~
2.9) at 4 pin of
OSC202
Yes
L206
Resolder or Replace the C239,
C222, R215