User Guide

PAMS
Technical Documentation
NSE–3
Disassembly & Troubleshooting Instructions
Page 23
Original, 11/97
Receiver Fault (3)
2nd IF
13 MHz
N620 pin 8(J542),
SL: – 28 dBm
N620 pin 44,
SL: – 19 dBm
N620 pin 47(J510),
~2.8V
Check VRX supply voltage
N620 pin 53(J554),
~1.2V
Check RXC control voltage
from COBBA pin 18
Change N620
VHFLO
Z620 input(J540),
SL: –26 dBm
Check R626 and soldered
joints
Z620 output(J538),
SL: –28 dBm
Check soldered joints, if OK
change Z620
N620 pin 34, SL: –36 dBm
and pin 35, SL: –33 dBm
N620 pin 34 and 35,
DC–level, ~1.4V
Change
N620
Check R628 and R629
N620 pin 29 and 30,
SL: – 29 dBm
N250 pin 22 and 23,
SL: –29 dBm
N620 pin 29 and 30,
DC–level ~1V
Change N620
Check soldered joints at N620 and N250, if OK change N620
Check connections between
N620 and N250
COBBA
YES
YES
YES YES YES YES
YES
YES
YES YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO