User Guide

PAMS
Technical Documentation
NSE–6
Disassembly & Troubleshooting Instructions
Page 26
Original 08/98
Receiver Fault (5)
VHFLO
Does the VCO oscillate at any
frequency ?
Change N540
Check VSYN_2
supply voltage
Check VCP voltage line
V621 collector,
~2.6V
V621 base, 1.7V
V621 emitter, 1V
Check V620, L629, C622,
C623
Check VSYN_1 supply
voltage line to V621
Check R623, R622 and
soldered joints
V621 emitter loading 330
Ω
if OK change V621
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
N540 pin 12, 2.3V
~
~
N540pins 9, 16 and 19 2.8V
N540 pin 13 and 22, 5V
~
~
~
~