Table of Contents
Advertisement
5-12 GSM Transmitter
Tx On (level : 5)
Pin 3 = 0.5~2.5 V
Pin 17, 18, 19, 20
Check U454
Pin 38 ≥ 2.5 V
Pin 35
SGH-N500 Flow Chart of Troubleshooting and Circuit Diagrams
Yes
U203
Pin 8
≥ 30 dBm
No
Yes
U203
Pin 5
≥ 30 dBm
No
Yes
U625
Pin 3
≥ 30 dBm
No
Yes
U476
Pin 1
≥ -10 dBm
No
U200
Yes
Pin 6
C204, R214, R217, R753, R203
≥ -10 dBm
No
U200
No
Pin 7
0.5 V
U200 Pin 3.
Pin 5 ≥ 2.8 V
Yes
Resolder U200 &
Check Pin 7, 5 path
U454
No
Resolder
OneC(U618)
≥ 40 mV
Yes
No
U454 (Pin35, Pin38)
0.5 V
Yes
Resolder
U618
Resolder
CN1
Check
VC1 : L
VC2 : H
No
Resolder
U625, C264
Check
U476 : +VBATT,
Pin 2 (APC)
OK?
No
Resolder
Check
No
pin 30, 47
OK?
≥ -10 dBm
Yes
Resolder
U454, U200
Resolder
Check U618
Yes
Change or Resolder
U203
Check
Ant. S/W Control Circuit
Yes
Resolder or
Change U476
Check +VBATT
or APC Control
U454
No
Resolder
U478
Yes
5-21
Advertisement
Table of Contents
