[Elecraft] KPA500 shutting down

[Michael Walker]

I run a remote base with a KPA500.  The Amp is a 3 hour drive away.

I can control just about everything remotely without effort.  The
installation has been rock solid for years (Flex 6300 / KPA500)  and lots
of chokes everwhere.

Last week the unit worked fine.  Today the KPA500 appears to shut down
based on the Remote GUI.

I will be on SSB, and then I see the bar at the bottom go to PWR OFF, reset
and go back to Powering ON/ Amp On.  This is when the amp is only producing
about 300 watts peak (about 24 watts drive).

There are no error messages displayed at all and the only thing I suspect
it might be is low AC voltage into the amp.

RF could be the problem, however in 2 years running contests, this is the
first time I have seen a shutdown like this.  I run many Mix 43 chokes on
all coax and signal lines.

Are there other messages I can see by monitoring the Serial port at all?
Any thing else I can do remotely?

I can recreate this on 160/80/40m.  Those antennas are at least 150 ft from
the station.

Also, at times, the GUI will seem to freeze.  The buttons work, but the bar
graphs are stuck frozen in time at a peak reading.  Yet, I can power off
the amp when this happens.

Currently, the amp is about 34F ambient temp.  In the past, I have used it
well below that (-25F) without issue (last winter).

My question is to the Elecraft guru's.  Any thoughts?  I am trying to
retrieve more data from the KPA500 remotely.

Mike va3mw