[MrFixr55]

Since a picture is worth 1,000 words (or 10,000 of my words, attached below is a partial schematic of a Philco Model 20 Power supply section with the diode mod and fuse added:
   

It is not necessary to do this mod on sets with 5AR4, 84, 6X5, 7Y4 etc. rectifiers, as these tubes have a "heater/ sleeve" cathode arrangement, which are not likely to short.

I cannot remember where I learned of this mod, I did not think it up myself. I believe that it was from "Phil's Old Radios"; I am not sure. However, I gratefully give credit to whomever thought this up and first published it on the internet!