User Guide

PAMS
Technical Documentation
NSE–3
Disassembly & Troubleshooting Instructions
Page 26
Original, 11/97
Receiver Fault (6)
VHFLO
N620 pin 18, ~2.3V
Does the VCO oscillate at any
frequency ?
N620 9,22 and 25, ~2.8V
N620 17 and 28, ~5V
Change N620
Check VSYN_2(J508)
supply voltage
Check VCP voltage line
V581 collector,
~2.6V
V581 base, ~1.7V
V581 emitter, ~1V
Check V580, L581, C582,
C583
Check VSYN_1(J516) supply
voltage line to V581
Check R581, R585 and
soldered joints
V581 emitter loading ~330
Ω
,
if OK change V581
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES