[Arran]

Well I replaced the 10 mfd cap with a new one and, as I figured, no change. Same current draw. So I tried to further isolate the problem by concentrating on just the power supply section around the rectifier tube. Long story short, I had everything BUT the transformer disconnected from the circuit, even the line cord and the transformer itself was still drawing 5 amps at 50 volts. I compared it with a known good transformer connected the same way, and there was no current draw to speak of up to 120 VAC. So, after double checking everything, again with the transformer itself isolated from the rest of the radio (it was disconnected from the circuit at the first 8 mfd cap #98) I am confident the culprit is a bad transformer. Not the news I wanted to find.

So now I'm faced with trying to find a rather large, flat transformer (it measures 2 5/8" tall, by 3 7/8" wide, and  4 3/4" long) with a 120 VAC primary, and secondary windings of 5.0, 6.3, and an (approx.) 600 volt winding with center tap.

Anyone know where I could find something like that, that would look like it belongs on the chassis? Since the transformer sits out in front, it's plainly visible, and I'd hate to put a new-looking modern replacement there.

 Maybe there is an issue with the filament wiring, that is unless there is a something connected to the transformer center tap that could cause the problem? By isolating the transformer you mean that absolutely everything is disconnected from it? The only other possibilities other then a shorted winding is that the windings are shorted or  are suffering leakage to the iron core, or that one of the leads is shorting to the cover through a break in the insulation.
Regards
Arran