User Guide

NSW-4
Disassembly & Troubleshooting
PAMS Technical Documentation
Page 25
Issue 1 Final Draft
08/00
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Apply 879.00 MHz
–116dBm , 8kHz dev, 1
kHz sine signal to
the antenna pad
Check 3 multiplier
output level C745
N700
V: >80 mVpp ?
N
N
N
Check input level
at duplex filter (Z910)
input
P:
≅
50 dBm
Check input level at
frontend (N701) input
pin7
P:
≅
–55dBm
Check output level at
LNA out
pin10
P: >–50 dBm
Connect EXT HS to
audioanalyzator, open
audio
AF: 1 kHz sine signal,
meas SINAD
AF: >12 dB
Check UHF Vcnt at C822
V: 2.0 ..3.5 V
Start synthesizer
troubleshooting
AMPS
RX–chain OK
Y
N
N
Y
N
Start synthesizer
troubleshooting
Change diplexer
Z970
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 = gain is in low state
Check MXR RF level
pin12
P:
≅
–55dBm
Change RX band filter
Z701
Check MXR IF level,
F= 116.19 MHz
P:
≅
–50dBm
Check LO input level at
N701, pin1 P
≅
0dBm
f=995.19 MHz
Note!
Check all soldering
N
Y
Note!
Check all components around N701
N
Y
N
Y
Apply 879.00 MHz
–50dBm , sine signal
to antenna pad.
Change N701
Start synthesizer
troubleshooting
Y
N