VS300 Troubleshooting Manual Responding to alarms
Page 1-2 Issue 6.0 2014-11-01
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 an alarm” on page 1-4 to determine the
remedial action required 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 an alarm” on page 1-4 to
determine the remedial action required 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 330 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.
