- 2024
- Aug
- 7
The 2024 Miami Valley Steam Threshers Association Show
While this, and other engine shows I attend aren’t necessarily electrical in nature, they are certainly prime examples of old technology. I’ve always found the mechanics of such devices to be fascinating, and worth my attention.
The MVSTA show is one that happens on the Western edge of Columbus every year, and I try to make it out there at least every few years. This year’s show was bright and sunny with no threat of rain anywhere. Prime viewing time for all of the mechanical eye candy that showed up.
I don’t have much to say about these pictures, so no annotations.
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Visit this link for more information on their shows.
- 2024
- Aug
- 7
Have you ever wondered what’s inside of that device?
Worry no more. With the help of Google Translate, you can finally see what’s actually inside that cheap Chinese solder pot you bought from AliExpress.
That magic “Heating Stuff” - it’s like the smoke in resistors.
- 2024
- Aug
- 7
The Columbus 2024 Hamfest
This year’s show was maybe 2/3 the size of normal - I suspect the dangerous looking skies kept some people away, but fortunately the rain held off for the show. It was, however, sticky enough that you could probably have put a straw in the air and drank some.
There were still some interesting things to be found at this year’s show, and some good deals to be had. This is what I saw this year:
- 2024
- Aug
- 7
My haul from the 2024 Columbus Hamfest
I brought home some things that I didn’t need, but isn’t that the point of this kind of show?
A Vishay decade box and a frequency counter / generator. They both seem to work well enough for the age. There’s also some high-voltage mica capacitors sitting on top of the decade box. Those were a buck, and I said why not?
I can’t go to a show without bringing home at least one meter. Unfortunately, this one seems to have some issues, it will zero but not read. I need to open it up and make sure that any batteries left in it aren’t corrodeedoodled all over the place.
This PACO generator is the same as one I have in better condition. This one is a $5 parts unit.
This is a PACO power supply that came from the same vendor as the generator, also $5. It’s an interesting piece, being an early bench supply for audio work, but in reality it’s a glorified battery charger. Stay tuned for a teardown on this guy.
No idea what this is, my fellow show-goer suggested it was some sort of early electronic switch for process industry. He’s probably right, but I got it simply for the cheapness of a 250VAC transformer that could be reused.
That’s it for this year. I’ll be posting show pictures, and some other, recent engine shows as soon as I can get the images cleaned up.
- 2024
- Aug
- 4
It’s time to clean out some stuff - maybe to Dayton 2025?
One of my fellow show-goers was talking about taking some of the audio gear he collected to Dayton in 2025, and we’ll set up a table on the flea market. This sounds like a cool idea to me, I’ve attended shows but never had a sales table.
In the spirit of things, I took a look at what I’ve collected over the years that’s never going to go anywhere, and there’s a bunch. It’s time to start cleaning out, and I have a bunch of things that could go. Where does it all come from?
See you there, and maybe you can take something home! It’s cheap cheap cheap!
(If you see something you like, drop me a line on LinkedIn and we’ll see about a deal!)
- 2024
- Aug
- 4
Pictures from recent shows are on the way!
Pictures from the Columbus Hamfest, Cool Spring Power Museum, and Miami Valley Steam Thresher Association shows are all in the works. There’s simply a lot of them and I have been a lazy little pig. Check back in the next few weeks and I promise that you’ll have some cool stuff to browse!
They’ve all been posted! Sorry it took so long on some of those…
- 2024
- Aug
- 4
The dial lamp can be more important than you think.
You’ll notice there’s a #47 lamp (Part# LM1) in the circuit for a lot of transformerless sets like the S-38C. It’s fed by a special tap on the rectifier tube:
It’s just a light bulb, right?
Yes and no. If you look at where it’s at in the circuit, it’s actually helping feed input current to the plate of the rectifier. This has the effect of both providing said current for the tube, and limiting the current available to the tube - you can draw about 60mA in this configuration.
So, do you need this bulb?
Again, yes and no. There are configurations where the tube is fed directly from the AC line, and this is a perfectly acceptable method. However, in our case of having the bulb, you have a bit of voltage drop to the plate which results in a lower output voltage, so you’d need to take this into account if removing the bulb - i.e. you need a resistor for some voltage drop. There’s also the fact that it is providing the AC current input - if you remove it, all of your current is now being sourced by the connection from the heater, and you’re stressing the tube. The radio won’t quit - but it just told you “Hey, I need service.”
In this case, the bulb is a component of the circuit that does more than provides light - it’s ballast for the rectifier and is providing a path for input current. It’s as necessary as the rectifier itself. You can’t replace this with anything other than a incandescent bulb without modification, so don’t grab an LED replacement for this one.
Fortunately, places like Antique Electronic Supply sell packs of 10 for under a fiver, so you can pick up a bunch and drop them in your parts bin. You probably want to do that anyway to get one that isn’t more tungsten boil-off than light bulb.