Voxtel BD20, Руководство по обслуживанию

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5-10
Troubleshooting
Check for:
• U206 soldering.
• U206 pin 5, 25, 28 (DC 2.85V).
Replace U206 if defective.
YES
START
NO
YES
YES
NO
NO
NO
Check
VC-TCXO U200 pin 3:
Frequency = 13.00 MHz?
Power -15 dBm?
Set
• Phone : Test mode
62 CH, 7 level setting (TCH)
62 CH, -60 dBm setting (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 soldering.
• Ulysse-Nausica.
• S/W.
Check for:
• U206 soldering.
• U206 pin 5, 25, 28 (DC 2.85V).
Replace U206 if defective.
Check
RF Main chip
U202 pin 5, 6, 7, 8:
I/Q signal DC 1.35V & 0.5Vp-p?
=
>
Check IF
VCO U206 pin 26, 27:
Frequency = 798 MHz?
Power -25 dBm?
=
>
Check RF 2
VCO U206 pin 23, 24:
Frequency = 1301.4 MHz?
Power -25 dBm?
=
>
=
>
Go to A
Remarks
1. 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.
2. Oscilloscope : 500mV/div, 2ms/div
5.10 TX Power Trouble (E-GSM)