Rebuilding A 1940s TV


There’s a lot of cool stuff to be found under piles of trash in an antique store. [dijt] discovered this when he found a tiny 7″ Motorola television from the 1940s under a stack of trinkets from earlier eras. We can understand [dijt]’s impulse buy, and the trials of rebuilding this ancient TV more than qualifies it as a hack.

If you know where to look, there are hundreds of resources available for old televisions, Hi-Fis, and radio equipment from the dawn of the electrical era to the modern day. After consulting with a few forums, [dijt] got his hands on a schematic for his television set and began work on diagnosing what was wrong with it.

It turned out the original ballast tube in this set had long since given up the ghost. Luckily, this is a common problem in old TVs, and after consulting some forums [dijt] had a schematic to replace this ballast tube with some newer caps and resistors.

After constructing the circuit and testing it out, [dijt] mounted it in the old ballast tube to replicate the original look and feel of the 1949 television. Interestingly, this is the second time this TV had been restored; the 1960s-era caps and resistors told [djit] this TV had once went into a television repair shop. Let’s just hope [djit] remembered to glue the schematics to the inside of the chassis this time.

30 thoughts on “Rebuilding A 1940s TV

    1. Thanks for the encouragement, and good luck to you as well! Are you by chance interested in a hackerspace tool exchange? I could use that CRT tester on these replacement tubes I scored…Also, thanks for catching the name difference ( dijit ). I didn’t want to nitpick, and I was just happy to have this posted. BTW, I love your ‘retrotechtacular’ looking WP theme, nicely done!

      1. Thanks — the base theme isn’t mine, though I did have a lot of fun with the pixel art and detailing.

        I’m happy to lend out the CRT tester, but I fear shipping from Vancouver to Pittsburgh (?) might cost you more than you expect. Email me if you’re interested.

  1. Well done and good luck to you. That electrostatic CRT has held its vacuum for 60 years and your HT and EHT is up. You’re off to a flying start.
    Well done for treating this rare survivor with the reverence that it deserves.

    1. I really do wonder how much of today’s technology will be about and repairable in 60 years time. And in saying that I fully expect 120 year old tech to be just as repairable in 60 years time.

    2. Thanks for the positive feedback! From what I have gathered on the many antique TV forums this set is in exceptional condition both physically and electrically. Even the mask that surrounds the CRT (as seen in the cabinet bordering the CRT) is in great shape. A nice re-finish on the cabinet, some original or repro replacement knobs and decals, and this set will be a beautiful example of quality craftsmanship from America’s golden years. I promise not to let any reality TV shows or miley cyrus touch the cathode rays. I am open for suggestions on the first television show to play on this set in more than 40 years….

    1. bonus points humbly accepted. In the antique store I only saw the back of the case and, since it is missing the heat-shield cover on the back, only the CRT socket, vacuum tubes, and a bunch of wiring was visible. The owner of the shop had to clear away a bunch of various trinkets stacked on or around it. Once I saw it uncovered I could no longer fight what I refer to as my ‘little hacker within’ that demands I get into as many projects as possible and spend all my free time and money working on things like this.

  2. I have to admit, I totally geeked out when I saw this was posted on HaD…it was validation of years spent in my garage and basement (and now a third, auxilary shop in the shed). This was a really fun project, and I was lucky to find a ton of resources such as,, and . Those guys really know their stuff, and are eager to help. The schematics are equally as beautiful as the mahogany case that will be restored next. I have a picture on the CRT, but the vertical sync is causing problems and you can barely make out the image. I am deep into that circuit and will likely have to replace the 60’s era caps and resistors. I will post videos as soon as I get a good picture. The kicker that sealed the deal in the antique store was that the owner threw in a box of CRT tube replacements for this set!! I have plans to turn them into homebrew “O’scopes”…. thanks again for posting! next up is an HHH submission

    1. Get this working as a TV and, if you can bear to part with it, it’ll probably be worth quite a bit of money. Or you could say you’re keeping it to leave to your grandkids, which means you get to keep hold of it.

  3. My vote for first tape feed has got to be some original episode of “The Outer limits”
    I Always loved that intro. (just the intro only here, ? a bit clipped looking somehow )
    just recently watched a few episodes online and I think it still works well in my little brain.

    Funny how this sets off some sorta post apocalyptic scenario vibe for me.
    meaning that I haven’t had a working TV in the house for almost a decade.
    have used a ATI vidcard in the pc to handle the vcr needs.

    to finally get my rambling point, I’m just thinking about the idea
    of turning on any old (working) CRT
    …..and there’s nothing to tune in….
    sort of like in those “last man left on earth” type flicks.

  4. Every time someone mentions our signals out in space the signal that comes up first is… I Love Lucy! Don’t forget, who made Star Trek. Desi Lou Productions. Jackie Gleason was shown alien bodies.
    I made a TV into a o’scope back in the late 60’s with magnetic deflection because I didn’t want to spend $4.95 for the plans.

  5. I’d be genuinely worried about radiation from a TV that old. I’m not sure they realized all the risk of radiation back then.
    And perhaps we went full circle since I have the impression we are once again in an age where at least the american population thinks radiation is a harmless thing under all circumstances

    1. Yes, they did know about X-rays, but black and white sets usually did not produce any (certainly this small set doesn’t have high enough anode voltage). Color TVs used leaded glass CRTs to absorb X-rays, which is why there was an issue with CRT disposal.

      1. You are correct about the X-ray emissions, however most of them came from the fly-back transformer and many of the high voltage power supply tubes in the back of the set. If you read on some of the sleeves the tubes are in there is and X-ray warnings

    2. Inverse square law, just sit a bit further back. Although this thing’s probably too precious, not to mention being black and white and a tiny screen, for regular TV viewing. I think he’d only use it on special occasions.

      Although I’d love to be wrong about that. It’d be great for Dijit to throw a TV party, get yourselves dressed up in some space-age polyester and eat whatever snacks and TV dinners people ate in the late 1950s.

      I actually have dreams where I find old TVs like this. Semi-regularly! One of my favourites is a tiny portable with a 1-2″ screen that runs on a 9v battery. It’s completely imaginary of course, but they’re cool dreams.

      The closest I’ve been to owning one is seeing it in a second-hand shop and being unimpressed by how much the guy was asking for it. But he was probably doing right.

      Remember the Simpsons episode where Homer and Abe go back to the old farm? Where the TV was in the corner there’s scorched walls with a shadow of young Homer sitting down imprinted on them.

  6. Just by coincidence I was watching Dr. Who – The Idiot’s Lantern while reading this thread! I have great respect for those daring to take on and restore these marvels of old!

  7. Remember kids, if you’re working with tube electronics (whether transmitters or receivers): 1.) Never assume a circuit isn’t live 2.) Never assume a capacitor is discharged 3.) ALWAYS work with one hand behind your back (better to burn your finger tip than stop your heart)

    Now go have fun!

    This is an awesome hack! Nicely done.

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