User Guide

NSW-4
Disassembly & Troubleshooting
PAMS Technical Documentation
Page 27
Issue 1 Final Draft
08/00
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Apply 879.00 MHz
–50dBm signal to
antenna interface
Check 3 multiplier
output level at C745
V: >80 mVpp
N
N
N
Check input level
at duplex filter (Z910)
input
Check input level at
frontend N701, pin7
Check output level at
LNA out, pin10
Check RF level of
COBBA_D
Check UHF VCO PD2
V: 2.0...3.5 V
Start synthesizer
troubleshooting
TDMA800
RX–chain OK
Y
N
N
Y
N
Start synthesizer
troubleshooting
Change diplexer
Note!
Check all soldering and components
in antenna circuit before changing
N
Y
Y
Change duplex filter or
L701
Note!
Check all soldering and discrete
components of frontend.
Change N701
Y
Note!
AG2 is on = low gain state
Check MXR RF level
pin12
Change RX band filter
Z701
Check MXR IF level,
F= 116.19 MHz
pin14,
Check LO input level
of
of N701, pin1
f=995.19 MHz
Note!
Check all solderings
N
Y
Note!
Check all components around N701
N
Y
N
Y
Change N701
Start synthesizer
troubleshooting
N
Y
NOTE! If AMPS RX check is OK, then only
components in AGC1, OUT_rx, IN_rxif and
OUT_rxif –lines needs to be checked.