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
Check RF
Level at C229
> -57dBm
Check RF Level
both side at C302
> -60dBm and
Almost Same Level
Check IF(360MH z)
L evel at C229 >
-30dBm
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
No
Replace or Resolder the CON101 &
Yes
Check the Crack
No
& Soldering of
U101
Yes
Resolder or Replace the
U101
No
Resolder or Replace C302, L 207, L208,
Yes
No
Yes
No
Res older or Replace the F204, L 204, C228,
Yes
No
SAMSUNG Proprietary-Contents may change without notice
SGH-A500 Flow Chart of Troubleshooting and Circuit Diagrams
C112
Check 0 ~ 0.5 V
at 2 pin, 10pin of
OK
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
Level(>-5dBm) and
No
Frequency
(1307.4MHz)
RF_Out of OSC201
Having Some Defect at B'd → Need To send
Yes
Check
No
Level(>0.6Vpp) and
Frequency(13MHz)
of OSC202
C234, L218
Check the 2nd Local
Frequency(1440MHz)
on beside the 38 pin
of U202
6-7
U 101
No
pin of U 601.
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
Resolder or Replace the OSC202, R226,
L206
No
Resolder or Replace the C239,
C222, R215