VK Corporation VK2000+, Service Manual

Page: 65 / 76

VK Quality Group GSM C/S
☞
☞
RX Sensitivity Trouble (E
RX Sensitivity Trouble (E
-
-
GSM)
GSM)
START
Check
RF connetor J601 pin 1
Frequency & power.
Frequency = 947.4 MHz
Power > -70dBm
Check
ANT Switch U604 pin 3, 2
Frequency & Power.
Frequency = 947.4MHz
Power > -70dBm
Check J601 soldering and short.
Replace J601 if defective.
Check :
• U604 soldering
• U604 pin 12 VC1
≤
0.4V (Low)
• U604 pin 13 VC2
≤
0.4
V (Low)
Replace U604 if defective
.
NO
YES
YES
NO
Set
• Phone : Test mode
62CH, 7level (TCH)
62CH, -60dBm (BCCH)
• Spectrum analyzer as shown in Remarks.
• Oscilloscope as shown in Remarks.
Remarks
1. Spectrum analyzer : SPAN = 1MHz
RBW = 3MHz
VBW = 1MHz
Press the trace key of spectrum analyzer on checking test
point and press the max hold key of spectrum analyzer
2. Oscilloscope : 500mV/div, 2ms/div
3. RF Cable Loss : about 0.3dB(KAE Cable)
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