The Stovebolt Site Forums The Shop Area The Electrical Bay The Radio Bench Bench DC power supply?

I am looking to purchase a power supply I can use at my work bench to test out my various 6V ( or 12V ) electrical parts. I recently picked up an NOS 54-55.1 truck radio.
I am under the assumption that even being NOS, it is still very likely in need of some replacement parts that may have degraded over time. Wax capacitors and the like. That said, I'd still like to safely test it ( along with a number of other parts ) and don't want to be pulling the battery out of my truck all the time to use it for this purpose. I like having the right tool for the job.
I'm wondering if the commonly available 30 Volt / 10 amp DC power supply units that can be purchased on Amazon for around a $100 or so be appropriate for this type of application? If so, can anyone recommend a unit you might have good experience with?

Thanks in advance for any assistance.

Congratulations on the radio find. That radio uses miniature tubes and doesn't use a whole lot of power. You could easily use a small battery charger that is good for about 6 to 8 amps. If it were mine, I would not power it up until all the "wax" or paper capacitors are replaced, but that is your call. I would replace the electrolytics in the can and purchase a solid state vibrator for it. Good luck and don't be shy about asking questions here.

Fred

Several of my friends and I have these and they are fantastic:

https://m.aliexpress.com/item/40010...amp;spm=a2g0s.9042311.0.0.2e8b4c4dcQyi9Y

Hi Fred ( truckernix ), I will take your advice and not put juice to the radio until it's been serviced. I found the manual/parts list for it online, and I'm wondering if there is a known list of the particular parts that need to be replaced and those that can be left alone? Or is that determined by inspection/evaluation. I am completely green with radio service procedures, do's and do not's, etc. Do you have any recommended viewing on youtube, etc. ? Or parts suppliers for the correct replacement items? Thanks so much.

Thanks for the recommendation, Fibonachu. I will take a look at it.

Generally speaking you will want to replace all the wax coated yellowish capacitors and the three that are in the big tin. I would also recommend replacing the vibrator with a new solid state model. You will need the schematic which I believe is online. I buy my capacitors from "Just Radios" as it is convenient for me. You can get help here and you can PM me anytime or send me an Email.

Fred

Radio restorers use a power supply with an adjustable current limiter (limits the current before it smokes).
Old radios sitting for a long time can have a multitude of problems.
Changing out NOS capacitors is good start but other NOS components age out as well.
If you hook it up to a 6 volt battery and turn the switch on, it can cause damage to good components so the most cautious move would be to isolate the other parts from the power supply and work in steps.
There are radio repair forums that have grumpy old guys just like Stovebolt that can help but you have to convince them that you are a novice and have a little electrical background.
If you want to do a complete restoration, you will need the test equipment to do an AM alignment.
Tuners pick up a lot of noise from dirty (dusty) bearings. It sounds scratchy when you tune it.
You need a professional grade cleaner and lube made just for electrical equipment and not spray lube from FLAPS which would be a catastrophe.

I believe I'm correct on this and I'm not sure of the year cutoff date for Delco radios.
The original speaker doesn't have a magnet to attract-repel the voice coil like a modern speaker and may have another coil that the amplifier operates.
It can be converted to a magnet speaker.

You need a bracket to hold the speaker and a bracket to hold the chassis. Message me for pictures.

The power supply I use on my bench is from the old days. It can be used for either 12 volts or 6 volts. It also has an adjustment that affects the voltage. In those days they didn't have solid state regulators. Also the supply is not capable of putting out too much excess current. It has a voltmeter and amp meter on the panel. As one uses a piece of equipment they become familiar with how it performs and to me that makes quite comfortable.

I stand behind my advice to replace the wax paper capacitors and the electrolytic capacitors. From a circuit point of view, it is safe to power it up at that point. There are some other small value capacitors that don't generally cause the same problems. They can change value and cause some problems. Generally most resistors will change value over time. Most are not precision types and if the nominal readings in operation are demonstrated, there is no need to replace them.

As far as alignment goes, specifically the IF strip, I like to check the operation of the radio first. If there is good sound reproduction coming out of the radio and good selectivity, I do not adjust the IF alignment. That also depends on the model. I have a signal generator that will give me additional information. There are radios around that have IF coil or capacitor trimmers that will actually fail or break if one tries to move them. So you can end up with a radio that is scrap after observing that it worked rather well before.

Thank you for the replies. I still want to get a bench power supply, but I'm now not real keen on putting power to my radio. I have other bits and bobs that need some juice to test. 6V wiper motors, switches, etc. I live in an area near Portland, OR where I'm confident I should be able to find someone that I can deliver my radio to have it worked on. I'd rather not ship it somewhere if I don't have to. I am okay with general electrical, but honestly I believe these radios transcend electrical into electronics, and while that may or may not be accurate... I feel it's beyond my abilities at this point and I would hate to let the smoke out of any old radio, much less an NOS 986771. There just aren't that many left to mess up!

It has kind of already been said, but to reaffirm: If you have a battery charger, you already have a bench test power supply. You can test anything on an old truck with a Charger. You can use an inline fuse if desired.

FIY: You don't test a switch with a power supply.

I agree with your opinion on the radio.

For what it's worth, my opinion: I don't like the radio on when I drive old trucks and they are AM only. Possible weak reception. They are great for filling the hole. You may consider using one for aesthetics. As thrilling as it is to get something N.O.S., a radio is not one of them. The refurbish cost is the same. Possibly sell yours and make a few bucks, buy a non runner, or a face, to fill the hole.

They do make modern look-a-like radios.

Repair shops don't like being dumped on.

If you send/take your radio to a decent shop and they know it hasn't been powered-up (they do the typical caps, cleaning and etc.) and it fails on power-up in a bad way, the repair person would quickly power down and start looking for clues (smell, heat, discoloration). Turn-around is normal and repair cost typical.

If you take the radio as it is and power it up yourself, if it fails and is taken to a repair shop, you have robbed the repair person of the clues (and first hand experience) they needed to locate the source of the problem. Troubleshooting takes longer and the repair cost goes up.

If a novice replaces the caps, it fails and the radio is taken to a repair shop (they can see the recent cap job), the repair cost would most likely be even higher. Your radio also may be assigned a lower priority and may sit on the shelf for a good while till other repair jobs are finished.

I fully appreciate your points. I'll take the radio, untouched, to whichever repair shop I go with.