Voxtel BD20, Руководство по обслуживанию

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5-14
Troubleshooting
YES
START
NO
YES
NO
NO
Check
RF Connetor ANT101 pin 1:
Frequency = 947.4 MHz?
Power -72 dBm?
Set
• Phone : Test mode
62 CH, 7 level (TCH)
62 CH, -60 dBm (BCCH)
• Spectrum analyzer as shown in Remarks.
• Oscilloscope as shown in Remarks.
Check for ANT101 soldering and short.
Replace ANT101 if defective.
Check for:
• U100 soldering.
• U100 pin 7 low voltage.
• U100 pin 4 low voltage.
Replace U100 if defective.
Check for U201 soldering.
Replace U201 if defective.
Check
RF 1'st SAW Filter U201 pin 3, 4:
Frequency = 947.4 MHz?
Power -77 dBm?
YES
NO Check for U206 soldering.
Replace U206 if defective.
Check
RF RFLO VCO U206 pin 23, 24:
Freuency = 1894.6 MHz?
Power -40 dBm?
=
>
Check
ANT Switch U100 pin 8:
Frequency = 947.4 MHz?
Power -72 dBm?
=
>
=
>
=
>
Go to C
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
5.12 RX Sensitivity Trouble (E-GSM)