Voxtel V310, Service Manual

Page: 41 / 66

5-18
Troubleshooting
5.15 RX Sensitivity Trouble (DCS)
Set
• Phone : Test mode
700CH, 2 level setting (TCH)
700CH, -60dBm setting (BCCH)
• Spectrum analyzer as shown in Remarks.
• Oscilloscope as shown in Remarks
REMARKS
1. Call connection : RF Repair’s Program , Rx test
a. Test mode init
b. Test mode set
c. Band , Channel set (DCS , 700ch)
d. Power Level SET (2 level)
e. Rx ON
2. Spectrum analyzer : SPAN = 1 MHz
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 10dB
START
Check
RF connector ANT 101 pin 2(C108)
Frequency = 1842.8 MHz
Power ≥
≥ ≥
≥ -75dBm
NO
Check:
· ANT 101 soldering and short.
Replace ANT 101 if defective.
Check :
· U100 soldering
· U100 pin 1 Low voltage
· U100 pin 6 Low voltage
Replace U100 if defective.
NO
YES
Check
ANT Switch U100 pin 4, 5
Frequency =1842.8MHz
Power ≥ ≥ ≥ ≥ -75dBm
Check VC-TCXO
X201 pin3 26MHz oscillation
Frequency = 26 MHz
Power
≥ ≥ ≥ ≥
-15dBm
NO
Check :
· X201 soldering
· X201 pin 4 DC 2.85V +- 0.1V
· X201 pin 3 DC 1.0 +- 0.1V
Replace X201 if defective.
YES