[PhilcoPhan1936]

Compare it to a xfmr from a similar radio (similar size xfmr and similar power requirements) while running for the same time. Transformers do get quite warm. But not very hot. However a real turn short (or many turns) will have a noticeable effect on the output voltage: if it is not there, then the xfmr is ok, and you might want to look at the load.

What kind of difference in output voltages should I be seeing? Running it at 108v out of my bucking transformer, I measured about 725v to the plates of the 5Z3, where the paperwork states it should be 830v. Which seems odd to me. If the resistance of the secondary is low (92.5/125 ohms), I would think the voltage would be higher on the output, not lower.
As a side note, I had forgotten that my step-father gave me his old Micronta analog meter, which is capable of handling 1000v, so I was able to test the secondary output voltage. My digital, I was worried I might top the 750v max and blow it.