Nautel GV10, Troubleshooting Manual

Page: 26 / 326

GV10/GV7.5 TROUBLESHOOTING MANUAL RESPONDING TO ALARMS
PAGE 4.1.18 VERSION 3.2 2016-03-10
Controller: SWR
Foldback Output Network
(amber) This alarm occurs if the transmitter's average reflected power exceeds the
SWR foldback threshold (400 W for all modes) due to a gradually degrading
load match. The forward power of the transmitter will be limited to a level
such that this threshold is not exceeded. If the load match improves while
the transmitter is producing RF output, the forward power will increase. If
the transmitter encounters a 3:1 VSWR (user-configurable) while in SWR
foldback mode, an SWR Shutdown alarm occurs. Inspect the antenna and
transmission line system for damage or de-tuning.
Controller: SWR
Shutback Output Network (red) This alarm occurs if the transmitter's reflected power exceeds the SWR
shutback threshold (1200 W). The transmitter will shut back and attempt to
find a safe operating point by entering its SWR foldback mode. This may be
the result of a transient SWR condition (arc or lightning) within the output
transmission line or antenna system. Attempt to reset the latched condition
by pressing Reset [using the AUI’s Reset button (see
“Reset:” on page
3.2.15
of the Operations and Maintenance Manual) or using the controller
UI (see
“Resetting Alarms” on page 3.2.104
of the Operations and
Maintenance Manual)]. Inspect the output transmission line and antenna
for punctures or damage. If no damage can be found, suspect the output
power probe (A15). See also Cutback Active alarm.
Controller:
Transmitter PA
Biasing - This is an informational alarm only that is displayed when the bias routine
has been initiated.
Controller: Turn On
Delay (Delaying Turn
On) Exciter (red) This alarm occurs, if the turn-on delay function is enabled, and transmitter is
not permitted turn-on until the delay period elapses. The turn-on delay
function is enabled upon an ac power failure and is typically used to add
delay for use with an external generator.
Controller: Very Low
Forward Power (Very
Low Fwd Power) Output Network
(amber) This alarm occurs if transmitter’s average forward power is below the low
forward power threshold (defaulted to 12.5% of the setpoint and is user
adjustable). Check for associated alarms, and follow the associated
troubleshooting procedure, if present.
Controller: +1.2V Fail Power Supply (red) This alarm occurs if the +1.2 V supply in the controller is 10% higher or
10% lower than its desired value. Check the output voltage of the LVPS
module. If necessary, replace the LVPS (see
“LVPS / Power Supply
Module Replacement” on page 4.1.50
). There may also be a problem
with the controller’s power supply PWB.
Device and
Alarm Name
(AUI, UI)
Controller Front
Panel LED (color)
Description and Troubleshooting Action