NV5/NV3.5 Troubleshooting Manual Responding to alarms
Issue 3.2 2014-12-10 Page 1-15
Controller: SWR
Shutback
This alarm occurs if the transmitter’s peak reflected power exceeds
the SWR shutback threshold [2:1 SWR, 600 W (NV5 or NV3.5) due to
a transient SWR condition (arc or lightning) within the output
transmission line or antenna system. Attempt to reset the latched
condition by pressing
Reset. Inspect the output transmission line for
punctures or damage. If no damage can be found, suspect a fault with
the control/interface PWB (A1). See also Controller: Cutback alarm.
Controller: SWR
Shutdown
This alarm occurs if the transmitter tries to reduce the forward power
below 815 W (NV5 or NV3.5) (FM mode), 582 W (NV5 or NV3.5)
(FM+HD mode) or 232 W (NV5 or NV3.5) (HD mode) due to repeated
SWR Foldback alarms (equivalent to a 3:1 SWR). The transmitter
latches off. See Controller: SWR Foldback for troubleshooting tips.
Controller: VDC A (or
B) Fan Fail
This alarm occurs if the fan A or B voltage, measured on the power
supply distribution PWB (A7), is below the low fan voltage threshold
(40 V). If there is an associated Controller: Fan PS A (or B) Fail alarm,
follow that alarm’s troubleshooting action. Verify the voltage on TP1
(A) or TP2 (B) of the power supply distribution PWB. If the voltage is
low, check the connections between the fan power supply module, its
PS interface PWB and the power supply distribution PWB. If it is OK,
suspect the control/interface PWB (A1).
Controller: Very Low
Forward Power
This alarm occurs if transmitter’s average forward power falls below
the low forward power threshold (defaulted to 25% of the preset
power level for all modes) due to module failures, combiner/filter
faults, reject load faults, or SWR foldback. If no other alarms are
being indicated, suspect the control/interface PWB.
Exciter A/B: Audio
Shutdown
This alarm occurs if the exciter’s audio processing and FM
modulation code is shut down. Should display only during a software
upgrade.
Exciter A/B: Analog
Left (or Right) Low
This alarm indicates the analog left or right audio input level is too low
(default threshold is 22.5 dB below full scale) or is not applied.
Exciter A/B:
Composite Low
This alarm indicates the composite audio input level is too low (default
threshold is 22.5 dB below full scale).
Exciter A/B: Dead Air This alarm indicates that the exciter’s audio modulation level is below
the level specified in the dead air settings of the active preset. Check
the appropriate program input(s) and the dead air setting for the
preset.
Alarm (with Prefix) Description and Troubleshooting Action
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