150 Part G: Alarms © Tait Electronics Limited December 2007
No PA detected The reciter cannot obtain a response from a PA over the using the control bus.
The PA may still be operating but the system has lost the ability to monitor PA
alarms, carry out diagnostics, change configuration, or detect PA fan failure.
1. No PA is installed.
2. Your system uses a third party PA which does not use the control bus and
cannot respond to the reciter.
3. The control cable or exciter cable is not connected.
4. The PA is faulty and unable to communicate with the exciter.
Fan failed The PA told the reciter that its fan is on, but the reciter cannot detect fan
motion. The base station takes no action when this alarm occurs, but it will act
if the PA temperature becomes too high.
The fan has failed. Replace it.
Shutdown The PA has detected a fault condition and has disabled the transmitter to
prevent damage. Check the other alarms to see what fault condition or
conditions have caused this.
VSWR high The VSWR is above the configured threshold. A normal VSWR is ≤ 2:1.
A high VSWR automatically means reduced output power. If the VSWR
increases to 10:1 or more, the PA folds back its power output to a minimal level.
If the VSWR returns to 5:1 or less, the PA recovers.
Check for a load mismatch on the PA’s RF output.
Power foldback The PA has detected a fault condition and has reduced its power output to a
minimal level to prevent damage.
Check the other alarms to see what fault condition or conditions have caused
this. If the fault condition clears, the PA automatically returns to its previous
power output level and the alarm changes to green.
Forward power
low
The PA forward power output is below the configured minimum limit. Check
the PA key line (there is no specific alarm for the failure of this line). If the
VSWR is also raised, check for a load mismatch. Otherwise, there may be a
fault in the output driver(s).
Reverse power
high
The PA’s reverse power is above the configured maximum. Check for a load
mismatch. With a resolution of only 1 W, this alarm is not sensitive if the power
output is lower than 20 W. Check the VSWR fault alarm instead.
Calibration invalid This alarm can only be triggered on startup, when the PA carries out self-tests.
It indicates that settings stored in firmware have values outside acceptable limits.
In response, the base station disables the transmitter. Re-calibrate the PA using
the Calibration Kit or send it to a service center for repair.
H/w configuration
invalid
The PA has an invalid hardware configuration. Either the driver is not present
or the configuration says that there is a Final 2 output stage but no Final 1,
which is impossible.
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