[Arran]

Let me guess, shorted or very leaky caps in the tone control assembly, it's a good thing you didn't run it too long that way otherwise you may have been shopping for another power transformer. I found a similar problem in a Canadian RCA model A-20, the tone correction cap across the output transformer primary had a dead short, result was the same, dead radio, but since I didn't have a 1 Kv replacement I clipped it out just to confirm and the radio came to life. 
Regards
Arran