[Diverted]

Thanks Millievolt. Maybe I should have been clearer. As I wrore in the original post, I do not plan to put any power to this radio until AFTER a restoration including electrolytics, caps, resistors cleaning etc. I wanted to know about the rectifier and transformer issues now so, on the chance the xfmr is bad, I wouldn\'t waste time starting a restoration on a dead radio. Rest assured everyone, I will do a a full work over; I just wanted some help on the 5U4 issue for now. Thanks!

You have more concerns than 5x4/5u4 substitution.  You can check that out with a tube manual or Duncan Amp web site.

Your 37 has the philco wire problem, hidden caps in the bakelite and IF cans and bad electrolytics that may have been wired wrong.

I would check the continuity of all major parts, power transformer, output transformer, IF's, all osc. and ant coils.  Then I would check resistors for opens and high values.  Then I would replace all caps.  Then I would make sure wiring is safe.

Much later, when you are ready to power up, I would use a variac or a dim bulb device and heavily fuse the power transformer.  These things are hard to get and expensive.

Good luck, millievolt