Nautel VS1, Troubleshooting Manual, Page: 27 / 109

VS1 Troubleshooting Manual Responding to alarms
Issue 10.0 2018-10-29 Page 1-19
Low Battery Exciter (amber) This alarm occurs if the backup battery voltage falls below an
acceptable level (2.7 V). The VS1 takes no action on this alarm.
Use a digital multimeter to measure the battery voltage (with ac
power on). If the battery voltage is low, replace the battery. If
battery voltage is OK, cycle ac power (off, then on). If the alarm
does not clear, suspect the exciter/control PWB (A1).
LVPS Fail
(+48V Fail)
PS (red) This alarm occurs if the output of the +48 V power supply (U3) is
outside of its acceptable voltage range (b43 and +53 V).
The VS1 takes no action on this alarm. Use a digital multimeter to
measure bV and -V of the +48 V power supply. If the
measured value is not within the acceptable range, replace the
+48 V power supply (see “+48 V Power Supply Replacement” on
page 1-40 ). If the measured value is within the acceptable range,
use a digital multimeter to measure the voltage between TP17
(+48V) and TP8 (ground) on the PS distribution PWB (A2). If the
measured value is not within the acceptable range, suspect the
connection between the +48V power supply and the PS
distribution PWB, and contact Nautel for further assistance. If the
measured value is within the acceptable range, check ribbon
cable W2 for damage and that W2P1 and W2P2 are properly
seated in A1J12 and A2J2 respectively. If there are no visible
problems with the ribbon cable, suspect the sampling circuitry on
the PS distribution PWB. If necessary, replace the PS distribution
PWB (see “PS Distribution PWB Replacement” on page 1-46 ). If
the alarm persists after replacing the PS distribution PWB,
suspect the exciter/control PWB (A1).
Mode/
Frequency
Mismatch
Exciter (red) For use with VS-HD exciter only. This alarm occurs if there is a
mismatch between the operating mode or carrier frequency of the
transmitter and the exciter. Suspect a possible communication
problem between the controller and exciter. The alarm should
clear once the transmitter transfers the preset settings to the
exciter.
No 1 PPS Exciter (amber) This alarm occurs if the pilot phase locking to 1 PPS is enabled
and the 1 PPS signal is not present. Check the 1 PPS input. If
there are no problems with the 1 PPS signal and connection,
suspect the exciter/control PWB (A1).The VS1 takes no action on
this alarm.
Alarm Name
AUI and
(Front Panel)
Front Panel
LED (color)
Description and Troubleshooting Action