Nautel NX15, Troubleshooting Manual

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NX25/NX15 Troubleshooting Manual Responding to alarms
Issue 5.0 2016-05-06 Page 1-17
Exciter A/B: Audio Loss This alarm occurs as a result of the modulation being below the
specified threshold for the designated period of time set in the
remote AUI’s Audio Loss tab for the current preset. This will cause
the action specified in the preset to be taken. Check the audio
inputs specified in the preset and verify there is signal present.
Exciter A/B: Audio
Overmod Protection This alarm indicates that the exciter has reduced the output signal
due to overmodulation on the audio input. This alarm is typically
caused by low frequency or excessive modulation, although it can
also occur if the DRM AES input sensitivity is incorrectly
configured, resulting in too much signal level. The alarm will clear
and allow the gain to return to 100% once the excessive
modulation condition disappears. Check the input signal being
applied to the exciter and reduce the level as necessary.
Exciter A/B: B+ Sample
Uncalibrated This alarm indicates that the associated exciter’s B+ sample has
never been calibrated. This alarm should only occur when
replacing an exciter, and indicates the configuration file was not
properly uploaded
(see “Digital AM exciter PWB replacement” on
page 1-55 ).
Exciter A/B: Carrier Sync
Unlocked This alarm occurs when the transmitter’s Sync Source is set to
GPS Sync Card or Combiner and the exciter cannot lock to the 1
kHz signal used for phase synchronization. If the Sync Source is
set to Combiner, this alarm will cause the transmitter to be
inhibited, otherwise this alarm is displayed for information only. If
the transmitter’s Sync Source is set to GPS Sync Card, check the
connection between the GPS sync PWB and the control/interface
PWB. If the connection looks OK, replace the GPS sync PWB
(see “GPS Sync PWB replacement” on page 1-61 ). If the alarm
persists, replace the associated digital AM exciter PWB (see
“Digital AM exciter PWB replacement” on page 1-55 ) or the
control/interface PWB (see “Control/interface PWB replacement”
on page 1-60 ). If the transmitter’s Sync Source is set to Combiner,
check the connection between the combiner and the control/
interface PWB. If the connection looks OK, troubleshoot the
combiner’s synchronization signal source.
Alarm (with Prefix) Description and Troubleshooting Action