The Variac that controls the Heat with Panel HC-1A had a failure of the top Variac.  

Christina notice a smell.  Chris S. Mark D. Richard M.  tried to locate the source which was a definite electrical odor.  Extended search desensitized us so brought in Ed M. and Corey G. .  Corey was able to narrow it down to the Variac associated with Heater HC-1A

I have shut down the circuit and opened up the unit.  Definite burn marks.