I would like to see if this old Airline brand portable tube radio from Monkey Wards still works, it uses a D battery but there is a lot of corrosion there, I can fix that. (The D cell is to heat up the tubes, I think).
But it also uses a 67.5 volt battery the size of half a loaf of government cheese, it looks like they don’t make those anymore.
I found a website that suggests using 7 common 9 volt batteries (presumably in series) but that sounds sketchy to me, and besides, it only adds up to 63 volts. I guess it couldn’t hurt to try. I have a variable DC power supply, but I don’t think it goes that high. Stay tuned for the exciting conclusion, where my wife is heard to exclaim, “WHAT is that smell? is something burning?”