VS2.5 Troubleshooting Manual Responding to alarms
Page 1-2 Issue 11.0 2019-05-10
On-air troubleshooting
On-air troubleshooting can be performed from a remote location, or locally at the transmitter
site.
Remote troubleshooting
Remote on-air troubleshooting consists of monitoring the transmitter's radiated signal using an
on-air monitor or via a LAN connection, and observing the status of each remote fault alarm
indicator. Information obtained from these sources should enable an operator to decide
whether an alarm response may be deferred to a more convenient time, an immediate
corrective action must be taken, or if a standby transmitter must be enabled (if one is
available). It is recommended that the significance of remote indications, and the appropriate
responses, be incorporated into a station's standard operating procedures. Refer to “Identifying
and troubleshooting an alarm” on page 1-4 to determine the remedial action for a given fault.
Local troubleshooting
Local on-air troubleshooting consists of monitoring the transmitter's integral meters and fault
alarm indicators. Analysis of this data will normally identify the type of fault, and in most
cases will determine what corrective action must be taken. Refer to “Identifying and
troubleshooting an alarm” on page 1-4 to determine the remedial action for a given fault.
The power amplifier stage contains an integral modular reserve (IMR) feature. This feature
permits the transmitter to operate at a reduced RF output level when a malfunction occurs in
one of its power modules. Station operating procedures will dictate whether a reduced RF
output level is acceptable. When a reduced RF output level can be tolerated, replacement of the
defective RF components may be deferred to a convenient time.
Off-air troubleshooting
Off-air troubleshooting must be performed when routine on-air calibration adjustments will
not restore operation.
It is recommended that the transmitter’s output be connected to a precision 50 resistive
dummy load (rated for at least the maximum transmitter power rating of 2500 W) before
starting off-air troubleshooting procedures. If an appropriate dummy load is not available,
troubleshooting for a majority of faults can be performed with the RF power stage turned off.
The transmitter may remain connected to its antenna system for these procedures.
CAUTION:
Reduce the RF output level to a minimal value when troubleshooting faults in the
transmitter. This is particularly important when the transmitter’s cover is removed -
where possible overheating could occur - or when the transmitter is connected to the
antenna system.
