Piecing together a vintage Radio Shack 150-in-One kit

Craig Smith (South Milwaukee, WI) wrote to me to share this amazing project he’s been working on and to ask for your help:

I was one of the lucky kids that received a Radio Shack Science Fair 150-in-One electronic project kit on Christmas morning. I spent hours making the different projects, such as sound effects, radio, light experiments, etc… I credit this toy as the reason I can solder up circuits from electronic kits or schematics, as well as circuits from scratch. As a teen, I robbed some of the components from the toy.

What started out as a project to make the incomplete toy whole again, I decided to make into a quality working wood replica art piece. Made from a piece of 1/4″ plywood and built into an old silverware box, I am using old beat-up junker kits to donate the spring connectors. I am locating as many new components as I can instead of using 30 year old components. I have the radio tuner parts, transistors, and 7-segment LED display.

But I’m having a heck of a time locating the input and output transformers. Also, the “advanced integrated circuit” is going to be impossible to find, not to mention the projects involving it weren’t that interesting. So I believe I will install the 555 timer circuit and include schematics in the booklet that would be interesting projects with the 555 timer.

Perhaps Make: Online readers can help me locate the proper ohm transformers, as well as provide other helpful and nostalgic tidbits on this toy that so many of us geeks got started with.

I definitely had one of these! Still do…er… someplace. How about you? Any helpful suggestions for Craig?

42 thoughts on “Piecing together a vintage Radio Shack 150-in-One kit

  1. The integrated circuit is relatively simple, I don’t see why you wouldn’t be able to just build it out of discreet components.

    If you’re looking to update it with a 555 why not also add an op-amp?

  2. The transformers were center-tapped on the high-impedance (1000 or 600 probably) side and 8 ohms on the other.
    Radio Shack carries these. The “advanced IC” was just a couple of NPN transistors wired up as a small gain low frequency amp

    1. I have the 200-in-1 kit from ~25 years ago. I still have the original box and manual. The transformers in mine look identical to those in the 150-in-1. The Output transformer is labeled “8” on one side and “900” on the other. The input transformer is labeled “2K” on one side and “4K” on the other. As someone else mentioned, both are center tapped on the higher side.

      Radio Shack sells one that seems very similar to the output transformer:

      The ICs on mine are different, so I can’t really help there. Mine are a 7400 (quad 2-input NAND) and a 7476 (dual J-K flip flop).

      1. You’re not EEVblog Dave are you? I watch that blog all the time. There was one with a 200-in-1 not too long ago that brought a tear to my eye. I had the late-80’s redesign, but the one in the vblog was an older one. Mine started to get run down and my dad made me throw it away, although I did get a 300-in-1 out of the deal. It had a breadboard. I still miss my 200-in-1 kit though. There are places that sell them still but they’re $50-60. Good memories. I once, somehow, managed to convert the “metal detector” circuit into a channel 2-13 tv jammer. Completely by accident. That was my proudest accomplishment. I thought I had the circuit copied down exactly but I could never duplicate it once I tore it down. I wish I could, I’m really curious just how much transmit power that was putting out.

  3. Had one of these, the “advaced IC” was really just a blob of plastic with a few discrete resistors, transistors, and diodes.

    Loved that old box. Got me into electricity when I was about 8 years old.

  4. Here is a link to an image of the kit:

    htt p:/ /i157. /t53/FlyVote/x150.jpg

    (Take the spaces out)

    The schematic of the IC was printed on the kit surface.

  5. I still remember spending countless hours with the 65 in 1 kit I received. One of my favorite gifts ever. I still have the kit.

  6. This is looking really nice! I got one of these when I was 7 or 8, and used it all the time. Just like you, I started pulling the parts out later in life. I think I still have the relay, meter, solar cell, and 7 segment display in my parts bins. Most of the other parts ended up in various projects. I’d love to rebuild one like yours for my son.

  7. I got the 200-in-one kit and did just about every project in the book. Still have the box and manual. It got me interested in electronics, but only at a basic level, not building from scratch. Hope to play with it again soon and with my son.

    1. I have the original 75 in 1 set that my father bought me in 1975. The Relay and OpAmp went bad in 1982 or so. I still use it today to teach Basic electronics to my BSA Troop12 unit in Connecticut. I recently bought a very new set from a Yard Sale for $15. I gave the seller $20 as I knew that the set retails over $80.
      This kind of stuff never gets old. I recently purchased a 1950 Oscilloscope, Frequency Counter, and Sine/Square wave generator.

      Ed Abbazia

  8. Thanks Dave for the coil ohmage. Book specs label them as ‘yellow’ and ‘red’, which back then indicated the range and style. (not a lot of variety back then)
    The IC can be borrowed from a junker kit. But the 555 has better projects associated with it.
    Transistor A had a 9 printed on it, book specs are PNP germanium RF converter. My replacement is a NTE160.
    Transistor B had 2SB56x on it, book specs are PNP germanium audio. My replacement is a NTE126.
    Transistor C had C711 92E on it, book specs are NPN silicon general purpose amp/switching. My replacement is a 2N3904.
    Any corrections are appreciated, as well as scources. Thanks guys

  9. The IC did have a diagram with it on the board. It showed the layout of 3 transistors and 4 resistors, but no specs on anything.

  10. If it’s supposed to be an “advanced integrated circuit,” why not replace it with a microcontroller and a USB programmer port. Not original equipment by any stretch of the imagination, but a cool way to fill the hole. :-)

    I remember not having much to do with that IC, whatever it was.

    If you want to stay analog, some op amps, like others have suggested, are a good idea. It’s kind of weird that it didn’t have that, now that I think of it.

  11. Craig,

    I have a complete kit here. What can I help with? Cool project, I’m excited to watch the progress.

    I kind of wish I could play with this, as the last time I used it I was under 8 years old (I’m currently 23). Unfortunately, I broke the “control” knob when I was little. Anyone know how to open this thing up?


  12. Josh,
    Actually, mine came with a red bulb so it may be original as well.
    The control knob is a 50K ohm varistor, trim-pot, potentiometer, whatever you want to call it. I got my 50K from American Science & Surplus for 75 cents. I think Radio Shack still stocks them. My vintage looking control knob I got at Ace hardware, one that has a huge selection of specialty parts in those slide-out bins.
    The cardboard surface is glued in at the edges, slide a steel putty knife down between the wood box and cardboard to break the glue.

  13. I found my manual for the 150-in-1 kit. In pieces…

    One thing written in it is a list of replacement transistors for A, B, and C made by an electronics instructor I had as a kid. RCA “SK” replacement parts. A, B, C in order:


    I remember him looking up those numbers from his revered “notebook of knowledge” – he likely had reproduced many of the circuits.

    Hope that helps.

  14. circuitgizmo,
    Hmm. You are the 2nd person to say that both A & B transistors are the same from their instruction book. My book says A is a 52 germanium, B is a 56 germanium. One project’s description stated either could be used, another project stated A was too sensitive and may be damaged. Later on they must have made them both the tougher 56.
    Thanks, I may take you up on the IC, but the 7 segment displays I can solder up myself with resistors because Am Sci & surp has BINS of LED displays in all sizes and colors for 25 cents apiece.

  15. I remember the two transistors as “being the same”. But I was 10-12 at the time. I no longer have the kit to confirm.

    I guess you can rebuild your kit to be “the same” as the 1977 kit, taking advantage of the 150 projects in the manual.

    Or you can add a 555 and make new projects.

    I don’t get a vote :-) but I like the idea of keeping it electrically compatible. You could, though, put the transistors and LED display into sockets to change as needed. I remember the 7-seg led as being a dim thing. Replacing with green or blue would rock. :-)

  16. Ok, who’s the young kid who had the nerve to call this thing “vintage” – I’ll hit ’em with my cane! ;)

    (Yes, I had one too as a kid and loved it!)

  17. Replacement springs from Radio Shack haven’t been available for 20 years. To buy 1/4″ by 3/4″ springs from a hardware store would be a small fortune. Even if you bought 6″ long springs and cut eight short springs from each… you would need to buy seventeen of them to get 125 springs. Best to buy a junker kit from a yard sale, Goodwill, Salvation Army, etc… and go from there.

  18. Was there a website made about this project? I’d love to find a source for the spring connections that is not just harvesting them from old junk kits. Components are cheap, what we need is some people to work on making projects that use common parts to compile into an instruction manual. Something like a copyright commons project lab.

  19. I really liked mine. Good luck on the build. I did a search on Google for those springs.. dang hard to find, but I did find one, but it was a China importer. Nothing on DigiKey.

  20. Fantastic! Firstly, can I just say to Craig, your project looks wonderful! Funnily enough, I was just contemplating doing something similar for my children using more modern day components like the timer chip you mentioned and some other CMOS chips as well. I found this article/post whilst looking for the manual for the 150 in one kit, as I just found my old kit in my parents Garage! Full of dust but all but for a couple of components here and there (a few resistors and capacitors, which I have now replaced) like Craig, I remember “borrowing” these for other projects as a teen…
    Strangely, the manual I have (which I discovered separately when going through some old paperwork, which is what prompted me to look for my original kit) is for the “100 in One” kit. It must have been mistakenly packaged with the 150 in One kit, because this manual & kit are all I can remember, I must have just made do and parsed the schematics/ wiring diagrams to suit the 150 in one…

    I wish I could help with the springs and transformer (my transformers are looking distinctly rusty!) but I’m having a hard enough time finding the proper 150 in One manual to download from somewhere! This is an old post now so I hope you have progressed further, I would love to see this project in finished form.

  21. I still have my 65 in 1 kit. I really enjoyed putting things together with that! The chip in question has been seen on another site on the web. Two transistors and a few resistors. I guess I need to shake the dust off that old box and take another look at it! You have really made your clone kit look nice. Good luck!

  22. Radio Shack still carries the output transformer (cat. no. 273-1380). I built a Science-Fair 100-in-One kit into an all wood console using the old parts. The 100-in-1 also has a special I.C. unit that I have easily duplicated with discrete parts. The 2N3904 and 2N3906 transistors work for me in every project as substitutions.

  23. i am hoping someone may have a copy or photo copy of 150 in 1 electronic project kit.i would pay for either one or the other and just wanting to leave it with instructions to my daughter when i am gone.its in real good shape and will stay that way till it is handed down to email is you for your time

  24. great job on the rebuild! how’s it coming along?

    did you ever identify the input and output transformers? i’d like to reproduce some of the schematics as stand-alone projects. i might even try winding my own, if i knew the number of turns on the primary and secondary.

  25. I may still have mine from my kit. One was red and the other yellow… Send me an email if you haven’t located already

  26. I was looking for information on the BA302 (the part number for the Integrated Circuit on my 150-in-one) and found that NTE has a cross-reference replacement part: NTE1431. A quick search on the internet shows these selling for about $4.00.

  27. I ran across this page while searching for the spring connectors. Does someone sell these, or do I have to salvage them from an old kit?

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Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy man’s memoir,” called Borg Like Me.

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