User Guide

PAMS
Technical Documentation
NSE–6
Disassembly & Troubleshooting Instructions
Page 23
Original 08/98
Receiver Fault (2)
1st IF
71 MHz
N500 pin 12,
1018 MHz SL: –28 dBm
G600 Out, 1018 MHz
SL: –28 dBm
Check connections from G600
to N500 pin 12
UHFLO
N500 pin 9 and 10,
SL: –28
N500 pin 6, 2.8V
Check VRX
soldered joints
Check R500
Rise up 9 and 10, if loading
OK at pads change N500
N500 pin 15,
loading 10 k
Ω
N500 pin 9 and 10,
loading 10 k
Ω
Change N500
Z502 input 1 and 2,
SL: –30
Z502 input 1 and 2,
loading > 1 M
Ω
Check input for
short circiuts, if
OK change
Z502
Check components in input
line to Z502
Z621 output,
SL: –43
Z502 output 1 and 2,
loading > 1 M
Ω
Check output
for short
circiuts, if OK
change Z502
Check components in
output line. Check soldered
joints at N540, if OK
change Z502
N540 pin 37 and 38,
SL: –43 dBm
N540 pin 35, 2.8V
Check soldered joints
of N540
N540 pin 37 and 38
DC–level ~1.7V
N540 pin 37 and 38,
loading 5 k
Ω
Change N540
Check N540 pin 37 and
38 for short circuit
2nd IF
13 MHz
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES