Nautel NX15, Troubleshooting Manual

Page: 23 / 274

NX25/NX15 Troubleshooting Manual Responding to alarms
Issue 5.0 2016-05-06 Page 1-15
Controller: Low RF Drive This alarm indicates the controller's RF Drive Duty Cycle meter
has fallen below 40% for longer than 10 seconds. This alarm will
cause an exciter changeover, if automatic changeover is enabled
and the transmitter is operating on the main exciter. If there are
two exciters in the transmitter, swap exciter positions. If the alarm
follows the exciter, or there is only one exciter in the system,
replace the digital AM exciter PWB (see
“Digital AM exciter PWB
replacement” on page 1-55 ). If the alarm persists, or the alarm
remains with the position, replace the control/interface PWB (see
“Control/interface PWB replacement” on page 1-60 ).
Controller: Out of
Memory Reset This alarm is only visible in the transmitter logs, and indicates the
controller automatically reset because it ran out of the memory
required to continue normal operation. If the alarm persists,
replace the control/interface PWB
(see “Control/interface PWB
replacement” on page 1-60 ).
Controller: PDM Latch This alarm indicates that the PDM latch circuitry on the control/
interface PWB has tripped, causing the transmitter to shut down
and latch off. If automatic changeovers are enabled and the
transmitter is operating on the main exciter, an automatic
changeover will occur, and the latch will be cleared, allowing the
transmitter to return to the current preset settings. If automatic
changeovers are disabled, or if the transmitter
was already
operating on the standby exciter when this event occurred, try
resetting the transmitter alarms. If the alarm persists, press
RF
Off , press the Reset button (S1) on the digital AM exciter PWB,
then press
RF On
. If the alarm persists, check modulation levels
being applied to the selected input and verify they are as
expected. If the alarm persists, replace the digital AM exciter PWB
(see
“Digital AM exciter PWB replacement” on page 1-55 ).
Controller: Power Loss This alarm indicates that the controller lost power at the time the
event was logged. The alarm should occur concurrently with other
alarms. Follow the troubleshooting action for the associated
alarm(s). Otherwise, if the alarm persists without the presence of
other alarms, replace the control/interface PWB
(see “Control/
interface PWB replacement” on page 1-60 ).
Alarm (with Prefix) Description and Troubleshooting Action