User Guide

PAMS
Technical Documentation
NSE–1
Disassembly & Troubleshooting Instructions
Page 20
Original 03/98
Receiver Fault (2)
1st IF
71 MHz
N500 pin 12,
1018 MHz SL: –28 dBm
G530 Out, 1018 MHz
SL: –28 dBm
Check connections from G530
to N500 pin 12
UHFLO
N500 pin 9 and 10,
SL: –28
N500 pin 6, 2.8V
Check VRX(J510) and
soldered joints
Check R504
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
Z621 input 1 and 2,
SL: –30
Z621 input 1 and 2,
loading > 1 M
Ω
Check input for
short circiuts, if
OK change
Z621
Check components in input
line to Z621
Z621 output,
SL: –43
Z621 ouput 1 and 2,
loading > 1 M
Ω
Check output
for short
circiuts, if OK
change Z621
Check components in
output line. Check soldered
joints at N620, if OK
change Z621
N620 pin 51(J530) and
52(J532), SL: –43
N620 pin 47, 2.8V
Check soldered joints
of N620
N620 pin 51 and 52,
DC–level ~1.7V
N620 pin 51 and 52,
loading 5 k
Ω
Change N620
Check N620 pin 51 and
52 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