[Reece]

Hi, I don't have the schematic and can't find it on Nostalgia Air, but this sounds like a typical four or five-tube AC/DC radio? When you install your 1N4007 diode, the band (cathode) on the diode goes towards B+: think of the B+ flowing out of the diode on the band end. You can use almost any resistor from 50 to 100 ohms, 1 or 2 watts should be OK, in series with the diode. When you install your electrolytics, be sure to disconnect the old ones as they can go (or maybe already are) shorted. Check how the new electrolytics are labeled because sometimes they can be confusing. They may have a stripe down the side with minuses on it, pointing to the negative end. The negative end will be the aluminum "can" of the cap, usually visible where the wire comes out. The positive end will have an insulating disc that the wire emerges from. Install exactly as the old ones were installed electrically.

It is recommended to replace all the paper caps in the radio with new caps.

To test B+ : set your meter to cover 120 volts DC, which may be the 200 volt setting? After your new 1N4007 and new resistor, there will be a filter cap, another resistor, and the last filter cap. Put your meter's positive lead on the + side of the last filter cap. Put the negative lead on the common point where the negatives of these filter caps come together. This point would also be the negative point for any other DC voltages on the chassis that you want to check. It would be good to use clip leads for this so you aren't "in there" with a live set. This is probably a "hot chassis" radio so you want to have sneakers on and a rubber mat on the floor, and don't touch the chassis while it's on unless you're insulated from ground. Good idea to keep one hand in your back pocket to avoid making a closed circuit! (Old radioman's trick. That's how they got to be old.)

If you have a variac, bring the set up slowly and watch for any signs of overheating or smoke (heaven forbid!) from any resistors, etc. Around 90 volts or so you should hear some crackles from the speaker, and it may begin to play.

If you don't have a variac, put a lamp socket in series with the power cord. Screw in a 60 or 70 watt lamp (incandescent bulb) and watch for untoward signs from the radio. Then go to 100 watt. Radio may start playing. If all is OK with 100 watt bulb, then plug the radio in normally.

I would not worry about getting the B+ exactly per the schematic: radio will work with the B+ probably within 10% of it. The filters store up some juice so that's why the voltage can appear higher than line. No reason why you can't use several resistors in series to attain the value you need. Just need to have room for them and proper support and ventilation.

You would find it easier to mount all these parts by adding a several-terminal solder-lug type terminal strip under the chassis.

Best of luck to you, and
Stay Insulated!
Reece