Harris Platinum Z2 CD, Manual

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6-18 888-2406-002
WARNING: Disconnect primary power prior to servicing.
Troubleshooting
6.9.21 AMB_WARNING, Ambient Temperature Warning
If the ambient temperature exceeds 50°C, the controller will switch the fan to high
speed. If the temperature goes down after high fan speed is initiated, the fan will go
back to low speed when the ambient temperature reaches 45°C (the hysterisis
between 50 and 45°C prevents the fan from quickly oscillating between low and
high fan speed).
6.9.22 AMB_TEMP, Ambient Temperature Fault
There are 2 thresholds associated with this fault, 60 and 65°C. If the temperature
continues to rise at high fan speed, after an Ambient Warning, then at 60°C the
transmitter is muted. If the temperature exceeds 65°C, then the transmitter is shut
off.
6.9.23 ISO_BZ, Over-Temperature
There is only one system ISO load in the Z2 transmitter and it is designated
ISO_BZ. It is the ISO load for the Z-Plane 2 way combiner and is located in the
middle of the Isolation Board. Its component designation is R9 on the Isolation
Board schematic. This load is protected by the System ISO Foldback routine. This
fault will not be reported in the Fault Log until it reaches 145°C. The following
paragraphsdescribe the Foldback and Fault levels.
6.9.23.1 System ISO Foldback
The Master Controller has a foldback routine it will use to protect the ISO_Bz load
called ISO APC Foldback. ISO APC Foldback uses 2 thresholds, 115°C and 130°C.
If the ISO_Bz load reaches 130°C the Master Controller will switch the fan to high
speed and start the foldback routine by reducing the APC voltage at a fixed rate. If
the temperature is reduced, the foldback will stop at 115°C. If the temperature goes
below 115°C the foldback will be reversed and the power will be very slowly
increased until the power output is back to normal or until the load temperature
again rises to 115°C at which point the power increase would stop. If the
temperature then rises back up to 130°C the foldback procedure will start all over. In
other words, the Master Controller is going to try and keep the load temperature
between 115°C and 130°C at some maximum power output. It is important to note
that no faults will be reported in the fault log for a foldback, only the foldback
indication while the overtemperature condition is present.
NOTE:
All PA and ISO temperature faults are based on actual thermistor tem-
peratures and/or a predicted value of temperature based on the rate of
rise in temperature over a given period of time. Therefore, a resistor
temperature which is predicted to reach 130°C will cause an overload
the same as an actual reading. Due to the prediction, it is possible to
get over-temperature faults even though the actual temperature read-
ing is not above the threshold.