Voxtel BD38, Service Manual

Page: 29 / 54

5-11
Troubleshooting
YES
NO
YES
NO
NO
Check VC-TCXO
U204 pin 3 13MHz oscillation:
Frequency = 13.00 MHz?
Power -15 dBm?
Set
¥ Phone : Test mode
700 CH, 2 level (TCH)
700 CH, -60 dBm (BCCH)
¥ Spectrum analyzer as shown in Remarks.
¥ Oscilloscope as shown in Remarks.
Check for:
¥ U204 soldering.
¥ U204 pin 4 DC 2.85V + - 5%.
¥ U204 pin 3 DC 1.4V + - 0.1V.
Replace U204 if defective.
Check for:
¥ U202 pin soldering.
¥ Ulysse-Nausica.
¥ S/W.
Check for:
¥ U206 soldering.
¥ U206 pin 5,25, 28 DC 2.85V.
Replace U206 if defective.
YES
NO
Check for:
¥ U206 soldering.
¥ U206 pin 5,25, 28, DC 2.85V.
Replace U206 if defective.
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>
Check RF Mainchip
U202 pin 5, 6, 7, 8:
I/Q signal DC 1.35V & 0.5Vp-p?
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Check IF VCO
U206 pin 26, 27:
Freuency = 766 MHz?
Power -26 dBm?
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>
Check
RF 2 VCO U206 pin 23, 24:
Frequency = 1364.8 MHz?
Power -30 dBm?
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>
START
Go to B
Remarks
1. Call connection : TEM3 execution
ti Enter
tms1
Enter
txpw 1 102 Enter
rfpw 2 700 Enter
rfe 7 Enter
2. Spectrum analyzer : SPAN = 1MHz
VBW = Auto
RBW = Auto
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 12dB
5.10 TX Power Trouble (DCS)