Reddit reviews Old Time Radios! Restoration and Repair

A few things:

1. Old radios don't usually run on as high a voltage as tube amps do. Most of the time, old radios don't have a power transformer and the filament voltages of all the tubes add up to somewhere between 110V-120V, so they don't need a transformer. High end radios sometimes have transformers, but not this one.
   
   
2. Yes, the capacitors are likely bad and you're right, those silver square things are capacitors. However, those are air capacitors for tuning the circuit and they don't go bad. The big black cylinder marked Zenith is the electrolytic capacitor used for filtering the AC, and it most likely is bad. That's a multistage cap with two or three sections inside, so you'll need two or three capacitors to replace it. There will be 8-12 other caps in the chassis, too.
   
   
3. Replace the cord, but also think about replacing it with a three wire cord so it'll be grounded. You should ground earth to chassis in case something shorts.
   
   
4. Don't just replace the old tubes. Most of the time, the capacitors are just bad in old radios. I've restored a bunch of sets like this and the tubes tend to be fine. Don't replace anything unless you're sure it's bad.
   
   
5. Get the old resistors out of there, too. They're all carbon comp and in all the years I've worked on electronics (since '98), I have yet to find an old carbon comp resistor that was still in spec. Plus they change value when they heat up. Go with metal film or wirewound, if possible. Those are much better.
   
   Check out some radio restoration books, like this one and you might want to pull some of the old Navy NEETS guides that cover tubes. Those are around the Internet and usually in free PDFs. A good place to buy parts is Antique Electronic Supply. I like to use Orange Drops as replacement capacitors, which they have. Also, you can order from the usual suspects, Newark, Mouser and Digikey.
   
   If you want a subreddit that solders, drop by /r/diyaudio. It's mostly hi-fi, but the tube fiends there love old radios, too.