NV5LT/NV3.5LT TROUBLESHOOTING MANUAL
RESPONDING TO ALARMS
PAGE 4.1.26
VERSION 3.3 2016-03-10
Rack #:
Communication Fail
(Comm Fail)
-
This alarm occurs if communication with the controller has been
interrupted. This alarm is typically only visible in the Events Log, since it will
not be transmitted when communication is interrupted.
Rack #: Discharging
PA Volts (Discharging
PA V)
PS (red)
This alarm occurs when the transmitter has initiated a shutback sequence,
and residual PA voltage energy stored in the capacitors in the power
supplies and PAs is being discharged. During a shutback sequence, the RF
drive to the PAs is turned off immediately after the event, and this occurs
faster than the power supply modules can be inhibited. Therefore, PA
voltage is still being applied to the capacitors with no drive to discharge the
energy. To discharge the stored energy from the capacitors, the PA bias is
increased to a discharge level after the power supplies have been inhibited.
This causes the stored energy to be dissipated through dc current in the FET.
This alarm should only occur with a Residual PA Volts Present alarm. See
Residual PA Volts Present alarm for more information.
Rack #: EEPROM Fail
-
This alarm occurs if the rack is unable to load its configuration from
EEPROM. This is a non-critical fault, since all of the information is
retrievable from the power supply modules and the controller.
Rack #: High Ambient
Temperature (High
Amb Temp)
-
This alarm is indication only and occurs if the transmitter’s ambient
temperature exceeds 60°C (140°F). Check the intake air filters or cooling
system.
Rack #: LVPS A (or B)
Fail
Power Supply (red)
This alarm occurs if LVPS module A (U2) or B (U3) is reporting a PS failure,
indicating its output voltage is outside its acceptable range, based on the
control setting. Check the dc output voltage of the suspect LVPS. If the dc
voltage is out of tolerance, replace the LVPS module (see
Supply Module Replacement” on page 4.1.46
). If the dc voltage is
acceptable, suspect the PS interface PWB (A1).
Rack #: LVPS A (or B)
AC Fail
Power Supply (red)
This alarm occurs if LVPS module A (U2) or B (U3) is reporting an ac failure,
indicating its ac input voltage is less than 175 V ac. Check the ac voltage
applied to the suspect LVPS module. If the ac voltage is acceptable, replace
the LVPS module (see
“LVPS / Power Supply Module Replacement”
).
Rack #: LVPS A (or B)
High Temperature
[LVPS A (or B) Temp]
Power Supply (red)
This alarm occurs if LVPS module A (U2) or B (U3) is reporting a high
temperature alarm, indicating its operating temperature has exceeded its
internal threshold of 105°C (221°F). This alarm is most likely caused by a
module fan failure or blockage. Allow the module to cool and attempt to
reset the alarm. Verify the module turns on and its fan is operational. If the
fan is not operational, inspect it for possible blockage. If necessary, replace
the LVPS module (see
“LVPS / Power Supply Module Replacement”
).
Device and
Alarm Name
(AUI, UI)
Front Panel LED
(color)
Description and Troubleshooting Action
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Page 307: ...VERSION 3 3 2016 03 10 MD 8 Figure MD 8 NAPA31C Power Amplifier PWB Q1 ...
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