User Guide

Flow Chart of Troubleshooting and Circuit Diagrams 5-21
5-12 GSM Transmitter
Tx On (level : 5)
U203
Pin 8
≥ 30 dBm
U203
Pin 5
≥ 30 dBm
U318
Pin 5
≥ 30 dBm
U476
Pin 1
≥ -10 dBm
U200
Pin 6
≥ -10 dBm
U200
Pin 7 ≤ 0.5 V
Pin 5 ≥ 2.8 V
Pin 3 = 0.5~2.5 V
Resolder
CN1
Check
VC1 : L
VC2 : H
Change or Resolder
U203
Resolder
U318, C264
Resolder
C204, R210, R211, R203
Resolder
U478
U454
pin 30, 47
≥ -10 dBm
Check 454
Pin 38 ≥ 2.5 V
Pin 35 ≤ 0.5 V
Resolder
U454 (Pin35, Pin38)
Check U618
Resolder
U618
No
No
No
No
No
No
No No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Check
Ant. S/W Control Circuit
Check
U476 : +VBATT,
Pin 2 (APC)
OK?
Resolder or
Change U476
Yes
Check +VBATT
or APC Control
No
U454
Pin 17, 18, 19, 20
≥ 40 mV
Resolder
OneC(U618)
Check
U200 Pin 3.
OK?
No
Yes Yes
Resolder
U454, U200
Resolder U200 &
Check Pin 7, 5 path
No