I forgot to mention in the video that the radio has an inverter circuit in front of the transformer for converting DC to AC. DC does not flow through or work with transformers but because this one is shorted the inverter circuit is bypassed and not operational so all the DC current flows through the shorted primary side of the transformer.

About 15 years ago, just before I was going to retire, I bought a bunch of old vacuum tube ham radios, Tektronic oscilloscopes and other assorted capacitor checkers and test equipment. I wanted projects to occupy my retirement years. Well, I'm just getting around to playing with some of that equipment but at 80 I realize that I'm not going to make much progress. So I guess I'll just start cleaning them up and turning them on as is to see if they at least power up. I've got a variac, isolation transformer and a variac with an amp and voltage meters. If I sold everything, my house would rise up about five feet from the loss of all that weight.

Good job 👍 . Learn something new every day !!

Ah yes, the old "dim bulb" test. I've got a set-up that has a variac, isolation transformer, fuse protection, and is portable!. Guess I'll have to do a video on it. Good things to know when you have to power up an old radio!

I just purchased a NOS 1987 Uniden Karate on eBay. I don't think it has ever been powered on. I am going to bring it up slowly on a variable power supply that I built back in high school Electronics class. I don't want to hit the electrolytic capacitors with 13.8 Volts all at once.

Wow I am jealous Rob. You have a variac. All you need now is an isolation transformer.

Well done! Question - when it comes to vintage microprocessor AC/DC transceivers, how would this procedure change, if at all?

You forgot to mention have a good Co2 fire extinguisher next to your work bench.

My radio TS 440S requires an external 12 volt power supply. It's been off maybe 10 years. Life happens. I have a lab power supply that adjusts from 0.00 v to 15.5 volts at a max current capability of 2 amps. The 440S draws about 2 amps on receive and if I increase the volts higher than 5.3 volts the amp meter pegs to maximum. So I hesitate to increase the supply above 5.3 volts. At about 4.7 volt one of the radio's feature indicator lights (Notch filter) comes on. I'm not certain about the accuracy of the supply's digital readout. The power supply amp meter shows 2 amps at 5.3 volts, so I can't yet tell if the electrolytic capacitors are shorted. I'm guessing I need a power supply metered and rated for more than 2 amps. Is my guess right? At the moment 5.3 volts isn't enough to run the receiver, so I really can't tell much. I suspect the receiver might begin to work at about 9 volts. I'm thinking I'll leave it on for a while until i can get a heftier power supply. OR I can use a bulb as you did. The radio has a built in frequency counter, but that hasn't come on yet. Do you have any further tips for me? Thank you.

I need a variac. Good stuff

Can I use like a very active bring the voltage up slowly check the power supply cap so they don't explode cuz the electrolytic dry out all that stuff

One main issue with your schematic representation of the Variac. A Variac is an autotransformer, and does NOT offer galvanic isolation as you have illustrated. This is an important detail that must not be overlooked, especially when working on equipment that has a "hot" chassis, not insulated from the mains! (Such as series string AA5 radios)

Ah good tips my friend!

Title: “Saftey (sic) Tips”

Transformers are Ac, not dc, you would never hook up dc to the input of the xformer. In fact, a transformer winding is supposed to look like a dead short to dc current. Otherwise your explanation is reasonable.