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Baldwin Microcomputer 236

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  • Baldwin Microcomputer 236

    Hey all. I've tried searching around for this particular problem, tried out a couple of things that I read but I'm not seeming to get any traction. So sorry if this post repeats something already covered. Feel free to point me in the right direction.

    I moved up from a half working Baldwin Fun Machine to a full on Baldwin MCO 236. I'm not even certain that is the right name. Very amateur organist but have always played keys of some variety.

    Two problems I'm experiencing: A loud buzzing or hum that always sounds as long as it is powered up. Surely this isn't just how it should sound. I have some mechanical and electrical inclination, but not in musical instruments. Any suggestions on where to start to find what's causing this?

    The second question: is it ok to not attach the pedals? I'm inclined to not want to have them on there, but it seems that the contacts on the bottom "sound" every so often, sometimes more sometimes less. It sounds like it did when I had the pedals attached and my kid would crawl by my feet and push them. Just wondering what the general consensus is.

    And question 3/2: the volume pedal appears to have a bad connection, it seems to give a lot of loud sometimes and barely any at others. I can't see any obvious bad connection in the wiring. Any advice?

    I know this is long-winded, but I'm just getting into this journey. I promise to pay forward any help I get and freely distribute my own knowledge as it grows. 😊

    Thanks! Let me know if I can clarify anything.

  • #2
    Congratulations on moving up to a larger organ. That's nearly always a good thing. The 236 was of course quite an amazing instrument in its day and would've been considered a dream come true for the aspiring organist. And it works equally well as easy-play fun machine and as real organ, so you get the best of both worlds.

    As to playing it without the pedals connected, that should not be a problem. If you are hearing an occasional pedal note sound, there must be something else wrong. Use a flashlight to look into the bottom of the organ and see if something is pressing down on the pedal switches. (And then again, I'm not even sure this organ has pedal switches in the console. They may be in the pedal board itself. But either way, it should not cause a problem just having the pedals disconnected, so your problem is elsewhere.)

    A continuous buzz or hum is no fun to have, so I'd sure try to sort that out right away. This kind of sound generally comes from either (1) a faulty ground connection within the system or (2) a failed filter capacitor in the power supply. (Assuming that it isn't actually a cipher, a note that is playing all the time.)

    These organs are so complex that it's going to take a lot of diligence to find the trouble. You probably should get a service manual from Robert Spoon. Email him at
    baldwinpartsguy [at] gmail [dot] com

    Using the service literature, locate the power supply and the various output voltages. Test each one with a DC meter scale to see if they are pretty close to specs, then test each one with the meter set for AC scale. On the AC setting, no voltage should show more than a few hundredths of a volt of AC present. A large AC reading indicates a failed filter capacitor in that leg of the supply, so you'll have to find the bad cap and replace it.

    I hate to bear bad news, but I believe that model is one that can be afflicted with a large number of failing capacitors on the circuit boards themselves. If so, it may turn out to be a huge project to get it repaired fully. OTOH, you might not have a lot of trouble at a given time, just find yourself replacing a capacitor now and then.

    If you do get into trouble with the leaking caps on the boards themselves, you may want to consider looking for a different organ. It might be hard to find another one that is so versatile, but then you may want to zero in on a model that best fits the style of organ music you want to play, be it classical or theater or pop music (Hammond style) or whatever.

    Good luck!
    *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!



    • M.C.I.
      M.C.I. commented
      Editing a comment
      Funny enough you describe it as a 'fun machine' - wasn't that an official Baldwin term?

    • jbird604
      jbird604 commented
      Editing a comment
      Yes. The "Fun Machine" was a popular Baldwin model. The OP moved up from a Fun Machine to a much more "real" organ.

  • #3

    Thank you. What a wealth of information! Definitely a place to start. At the moment, the buzz is tolerable to me, it still has a great sound, so I'll make it a project to try to spiff it up.

    My goal/dream is to have a Hammond B3, but as yet I haven't seen them for free. I got the 236 for free after a man who'd played it since it was new had passed away and it appears he took good care of it. There is a maintenance sticker on the back and I plan on contacting them to see if they have any information on this exact instrument.

    Sounds like I have some work ahead of me, I'm glad it's playable (in my opinion) so I can have some patience. It will be a good learning experience. I might be back with more questions or even to share what I learned. 😊

    Thanks again, John!



    • #4
      Well, I'm back again with slightly more info. I've been using the volt meter but still in a learning more. However, I've realized the sound (the hum) only comes from one speaker, namely the left-hand bass speaker (subwoofer?) that's on the side of the machine. I'm giving some thought to just disconnecting that speaker and see if that removes the hum. Any thoughts to that? Other than loss of some richness of sound?


      • jbird604
        jbird604 commented
        Editing a comment
        Won't hurt to try! Anything you can do to make the organ playable is an improvement. Of course the real fix is to figure out more about the circuitry and try to find the actual bad part. Disconnecting that speaker may rob you of a very great part of the organ's tone, but you won't know until you try. Don't do anything you can't easily reverse. I think the speaker wires are attached with removable lugs, and you only need to detach one of them to silence it.

    • #5
      Have you determined if any tabs or volume controls affect the noise? Have you tried adjusting the level set potentiometer to see if it affects the volume of the noise? It's located to the right of the power amplifiers.

      Also if possible do not touch, smile at, or in any other way taunt the 50+ plug-in circuit boards under that black cover. They will not take kindly to any human interaction.

      The audio channels at the ends of the cabinet have both a 12" and 8" speaker so you will need to disconnect both. The bass speaker is inside the sealed box in the center.