User Guide

CCS Technical Documentation RF Troubleshooting
Company Confidential NHM-10
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Set up Phoenix RF Controls
Band: GSM 900
Mode: RX Continuous
Channel: 37
Check VCO Out.
Is LO visible?
PLL is working
Check VR7 J618
.
Vge OK?
Check VR7 VCO
Side of R730.
Vge OK?
Change
R731
Refer to BB
Fault Finding
Does the VC
Vge change
when you change
channels?
Check T702
Balanced O/P.
Signal same?
Check T702 I/P.
LO Present?
Change
T702
Change
R730
Test with
Spectrum
Analyzer
Test with
Oscilloscope
Replace Mjoelner
Replace G701
Check Mjoelner Voltage Supplies
VR1A, VIO, VR3, VREF1. OK?
End
Action
Is LO@
3.77 GHz
YES
NO
NOYES
YES NO
NO
NO
NO
YES NO
YES
YES
YES NO
YES
Change Channel
to 975. Does LO
change frequency?
YES
NO
KEY
Check Loop Filter
Components. OK?
Replace Faulty Loop
Filter Components
Check /
Inspect
START
NO
YES
YES
850
190
3.53
220.