Nautel NV3.5LT, Troubleshooting Manual

Page: 40 / 324

NV5LT/NV3.5LT TROUBLESHOOTING MANUAL RESPONDING TO ALARMS
PAGE 4.1.32 VERSION 3.3 2016-03-10
RF Power Module Troubleshooting
Refer to “Operating with Defective or Missing RF Power Modules” on page 4.1.32 for removal and
installation instructions and then refer to “Troubleshooting RF Power Modules” on page 4.1.42 for
detailed troubleshooting information.
NOTE
: A defective RF power module can be removed for repair, without turning off the transmitter, as
described in “Removing an RF Power Module” on page 4.1.40 . The transmitter can be operated at a
reduced output power level with an RF power module removed.
Operating with Defective or Missing RF Power Modules
It is permissible to operate the transmitter with multiple defective or missing RF power module(s).
Table 4.1.2 on page 4.1.33 shows the approximate percentage of remaining output power (relative to
original) when RF power modules, power amplifiers (PAs), or power supply modules fail or are removed.
 If an RF power module has one or more defective PAs, as indicated by the AUI's Module Status
screen (and suspect RF power module's front panel LEDs), but is still contributing to the
transmitter's RF output, it may be left on. The transmitter will take necessary precautions to
reduce the stress on components due to the failure, i.e., power reduction.
 If an RF power module must be removed, turn it off prior to disengaging its blind-mating
connectors. Refer to
“RF Power Module Replacement” on page 4.1.40 to disable a module with
the transmitter on air. At all other times, turn off the switching power supplies by pressing the
RF Off
button, then switch off the ac power source at the service entrance.
NOTE
: There are many possible combinations of PA/module failures or extractions. The best and worst
case situations are shown in Table 4.1.2 on page 4.1.33 .
 When maintenance is complete and it is safe to return the transmitter to normal service,
enable all RF power module supplies by setting the switch on the front of the associated RF
power module(s) to its ‘
ENABLE
(up)’ position.
CAUTION! Do not attempt to compensate for power reduction caused by an RF
power module failure by adjusting the RF power level.