[Arran]

So all of the 6.3 volt tubes had open heaters? I have a 32 volt set where someone plugged it into the 120 volt mains and the way they worked it was that the 6.3 volt tube were in series across the 32 volts, but only one had the heater/filament blown open, one was still all right, and the other had poor emission, so one would think that the Philco 611 would have behaved the same, the weakest one would act like a fuse and pop before the other two? The 25 volt tubes have heavier heaters so no issue there, although in my 32 volt set they were connected across the 32 volt line, so they died with having 120 volts across them.
Regards
Arran