Nautel NV3.5, Troubleshooting Manual

Page: 21 / 228

NV5/NV3.5 Troubleshooting Manual Responding to alarms
Issue 3.2 2014-12-10 Page 1-13
Controller: Low
Battery/Memory Fail This alarm occurs if the backup battery voltage falls below an
acceptable level (2.7 V). Check the battery voltage (with ac power
on). If battery voltage is low, replace battery. If battery voltage is OK,
cycle ac power (off, then on). If the alarm does not clear, suspect the
control/interface PWB.
Controller: Low
Forward Power This alarm occurs if the transmitter’s average forward power falls
below the low forward power threshold (defaulted to 50% 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.
Controller: Low RF
Drive Power This alarm occurs - in analog (FM) mode only - if the active exciter’s
power is less than the low RF drive threshold (8 W). Increase the
exciter output power until the alarm clears. Check RF drive cabling.
Controller: Mode/
Frequency Mismatch This alarm occurs if there is a mismatch between the operating mode
or carrier frequency of the transmitter and one or more of the
associated exciters. Using the AUI verify the active presets of the
transmitter and exciter match. If necessary, set and save the
transmitter’s or exciter’s preset accordingly.
Controller: Module 1 -
2 Not Responding This alarm occurs if one or more of the RF power modules is not
responding to serial messages. Try swapping the affected module
with a module in another location (see
“Operating with defective or
missing RF power modules” on page 1-27 ). If the alarm follows the
module, troubleshoot or replace the module. If the alarm follows the
location, check the connections between the module location and its
associated module backplane PWB.
Controller: Reject A
Fan # (1-3 Fail This alarm occurs if one of the reject load cooling fans (1 though 3 in
reject load assembly A) is reporting a failure. With RF on, remove the
transmitter’s upper, back panels and check the associated fans for
blockage. If the fan is functioning properly (as compared to adjacent
fans), but the indicated fan speed on the AUI is zero, there may be a
problem with the fan’s tachometer circuitry on the control/interface
PWB. Disconnect the fan’s power plug and verify there is a nominal
48 V on the plug. If so, replace the fan. If not, suspect a defective fan
power supply module or interconnect cabling.
Alarm (with Prefix) Description and Troubleshooting Action