[davemc]

The original rectifier tube (80) is in place and tests good. My meters Fluke 75 and HP973 are very accurate and agree. The Variac dial also says 100 volts. The power transformer is original - no extra hardware has been added. Measured wattage (a REAL wattmeter) is normal (60 watts operating - but I do not have the specs) and no heat in the power transformer. Also, AC voltages on each side of the high voltage are within 1 volt. The power transformer has only one primary and no taps. The filament voltage measures 6.2 volts AC with 110 volts AC input - it measures low with 100 volts in (but the radio works OK).

One other thing: the Zenith (Zenette) 216-2 is a 25hz model! It works well on 60hz and the good folks on ARF said operation at 60hz would not be a problem. But I wonder if the result is that the B+ is too high operating on 60hz. On that set, I changed the input filter to 4mfd, but the B+ is still way to high (again, normal B+ with only 100 volts in).

On the Sparton, there is no label or model information - the set was identified from the schematic, part numbers, and chassis photos in Riders. So that set could theoretically ALSO be a 25hz model! The transformer on the Zenith is very large - not so on the Sparton.

I have had no problems like this with any other sets in my collection, at least operating at 110 volts (I run all my sets through a bucking transformer, unless the set has a 125 volt AC input tap).