VK Corporation VG207, Service Manual

Page: 31 / 70

5.12 TX Power Trouble (E-GSM)
START
Check
VC-TCXO
U200 pin 3 13MHz oscillation.
Frequency = 13.00MHz
Power
≥
-15dBm
Check
RF Mainchip
U203 pin 39,40,41,42
I/Q signal
≥
DC 1.35V
& 0.5Vp-p.
Check :
• U200 soldering.
• U200 pin 4 DC 3.0V + - 5%
Replace U200 if defective.
Check :
• U203 pin soldering.
• Ulysse-Nausica.
• S/W.
Check :
• U201 soldering
• U201 pin 11, 17, 24 DC 3.0V
Replace U201 if defective.
NO
YES
YES
YES
NO
NO
Set
• Phone : Test mode
62CH, 7level setting (TCH)
62CH, -60dBm setting (BCCH)
• Spectrum analyzer as shown in Remarks.
• Oscilloscope as shown in Remarks.
Check :
• U201 soldering
• U201 pin 11, 17, 24 DC 3.0V
Replace U201 if defective.
NO
Remarks
1. Call connection : TEM3 execution
ti Enter
tms 1 Enter
txpw 1 7
Enter
rfe 7 Enter
2. Spectrum analyzer : SPAN = 1MHz
VBW = 1MHz
RBW = 3MHz
Press the trace button of spectrum analyzer on checking test
point and press the max hold of spectrum analyzer
3. Oscilloscope : 500mV/div, 2ms/div
4. RF Cable Loss : about 10dB
Check
1'st LO VCO
U201 pin 10
frequency & power.
Frequency = 1229.4MHz
Power ≥ -22dBm
Check
2'nd LO VCO
U201 pin 23
frequency & power.
Frequency = 545.0 MHz
Power
≥
-15dBm