Now that I have access to the main unit the plot thickens. All of the outputs of the potted brick go to full-wave bridge rectifiers in the main unit such that you get a plus and minus voltage reference to the CT ( center tap ). That big potted POS is nothing more than a big friggin transformer ! The main output leads ( 1 2 and 3 ) have 28 VAC coming out of them. I put a Variac on the " transformer " and turned it up very slowly. At not much voltage it gets very HOT ( I suspect shorted windings or a whole shorted primary on the input side. The 28 VAC output figure came from estimating proportionally what the output voltage would be with a full 115 VAC on the input primary. I own this puppy now !! Best regards, Steven