The simplest would be to mount a thermal switch on the heatsink. When it closes fire a GPI.

 

Something like this at the temp threshold that you want to alarm:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=3455RC%2001000247-ND
Find out the temp were it's failing now, and select a switch maybe 5 or 10 degrees lower.

 

For the room temp, maybe a plain old thermostat tripping a different GPI.

Using one for AC/HEAT would give you high and low trip points.

 

This would at least give you some alarms.

 

Bob

WB3AWJ 

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From: "Scott Weis" <kb2ear@kb2ear.net>
I am having a problem with the hot weather shutting down a repeater. I would
like to know if anyone has any way of monitoring the ambient temperature in
the room as well as the surface of a heat sink and then triggering an event
in app_rpt when they exceeded a certain threshold.