Nautel NX15, Troubleshooting Manual

Page: 51 / 274

NX25/NX15 Troubleshooting Manual Responding to alarms
Issue 5.0 2016-05-06 Page 1-43
RF power module troubleshooting
Refer to “Removing and reinstalling RF power modules” on page 1-45 for removal and installation
instructions and then refer to “Troubleshooting RF power modules” on page 1-48 for detailed
troubleshooting information.
Module #: Low B+ voltage
A
Module # Low B+ Voltage
alarm is triggered when the B+ voltage is at least 10% below its
expected level.
1. If all RF power modules are reporting this alarm, it is very likely there is also a
Rack #: Low
B+
alarm. If so, the fault is not likely associated with an RF power module; proceed to “Rack
#: Low AC” on page 1-44 for further troubleshooting information. If not, proceed to
Step 2 .
2. Check and, if necessary, replace the fuse on the power module interface PWB for the
affected RF power module. Each power module interface PWB serves four RF power
modules and therefore has four B+ fuses (F1 through F4). Refer to Figures MD-1 and MD-2
in the Mechanical Drawings section of this manual to locate the associated power module
interface PWB and then refer to Figure MD-4 or MD-5 to locate the specific fuse.
3. Check and, if necessary, replace the affected RF power module. See “Troubleshooting RF
power modules” on page 1-48.
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 1-45 . The transmitter can be operated
at a reduced output power level with an RF power module removed.