Curious Marc Takes On Sewing Machine Repair

Even the most talented engineers can be stymied by simple repair projects. In this case, repairing a broken sewing machine has [CuriousMarc] all tangled up.  [Marc] is probably best known as a part of the team who managed to restore and boot up an apollo guidance computer, but he’s worked with plenty of other vintage machines.

This problem hit much closer to home. [Marc’s] daughter wanted to sew a Halloween costume. The machine would boot up fine, but when attempting to sew, it would make a bit of noise, then beep and display “The safety device has been activated”. Not very helpful.

The sewing machine in question is called “Baby Lock Decorator’s Choice” and is manufactured by Brother for Juken. [Marc] of course dug in, and quickly found himself stymied by a clamshell case that just didn’t want to come apart. This is the point where many of us would apply just a little too much force when prying and be rewarded with a broken case.

[CuriuosMarc] is thankfully the more patient sort. Rather than become [FuriousMarc], he carefully persevered to find a hidden screw holding things together. The screw could only be accessed by inserting a screwdriver through a tiny access hole on the front chassis of the machine.
With the screw out, a couple of molded clips were all that held the case sides together. After popping them, [Marc] was finally able to fix the real problem: A toothed belt that had slipped off its cog. That’s it — just a loose belt. The cryptic error code most likely was due to the machine realizing it the motor was on, but the machine wasn’t moving – which would generally indicate something stuck or tangled in the thread path.

This type of repair would be much easier if service manuals were readily available. We did a quick search for this model but didn’t find anything freely available.

Have you gotten stuck by a simple repair? Tell us about it down in the comments.

29 thoughts on “Curious Marc Takes On Sewing Machine Repair

  1. “The machine would boot up fine, but when attempting to sew, it would make a bit of noise, then beep and display “The safety device has been activated”.”

    The store where my wife bought hers, corrects anyone that uses the term “machine”. It is a “sewing computer”!

    It didn’t cost as much as a Lamborghini, but like one, it ends up in the shop on a regular basis.

  2. Bought my mother an embroidery machine a few years ago and it quit recently. It’d boot up and then the screen would go white and the buttons would ignore all input.

    A bit of digging I found the service manual and got it to boot into diagnostic mode. Physical buttons all worked fine but touchscreen diagnostics froze. It took about an hour to take the thing apart to reach the wiring for the screen, and it turned out the touchscreen’s flex-PCB cable had slipped out of one of those flimsy ribbon cable sockets. Put it back in and added a drop of glue to secure it, and it was all fixed.

  3. How dangerous to allow anyone to open the unit and attempt a repair. They could get hurt or killed. They should have sent it to a certified Brother repair center because they have no access, manuals, schematics, or parts. Take it from me … I know how these things should work …

    Bill Smith, John Deere service technician

  4. I have successfully repaired a Fender Frontman 212 guitar amplifier on which the clean/overdrive switching was obfuscated behind switches generating multiple voltages from two legs of opposite AC rectified and fed to zener combinations, then being fed to comparators and ultimately the result was fed to njfets to commute channels…

    It has been a nightmare to troubleshoot especially since the voltages indicated in the service manual were not the correct ones… there was one capacitor which turned bad and took its zener with him, simple enough but considering the initial issue was a hissing/screaching sound as soon as a string was pulled, nothing was indicating this kind of issue at start even if it is obvious that channels were simply mixed the wrong way

    This amplifier is marked as “do not repair” by repair services…

  5. did someone say sewing machine repair? obviously, i’m a fan of the old heavy metal sewing machines…and i got this surprisingly expensive book ‘the complete handbook of sewing machine repair’ by howard hutchison. this book is a throwback to the days when every book had a preface about how reading this book will help you save the world. a beautiful book, i read it cover-to-cover the first night i got it. literally couldn’t put it down. all my repairs on my 1960s-era machine have been really straightforward and honestly i didn’t really need to read that book. but those machines are really designed with maintenance as a primary goal.

    my wife has one of the modern plastic abominations. light as a feather, a zillion features. it kept jamming on her and she went through a surprisingly difficult diagnostic process that finally paid off when she was watching a youtube of someone loading the bottom bobbin, and she saw they did it backwards of how she did it. it didn’t even occur to me anyone would do it backwards like she was doing it. :) so it’s not always the modern machine being obtuse.

    1. I think my wife (at times) loaded the bobbin backwards into her “sewing computer”.
      It wouldn’t run, but didn’t say why.
      That thing is heavy hauling out to the car, and from the car to the repair shop…

  6. I’m confused by the need for a sewing machine to boot. My machine, whilst electric, doesn’t *need* to be plugged in to work, though annoyingly the manual handle is appalling ergonomically and it lacks the flywheel my mum’s has so it’s very slow by hand. But it’s still useful for neatly finishing things. And it’s got a mechanical auto threader.

      1. I once saw a Singer machine that needed pedalling. But it looked identical to my mother’s which ran off electricity. So I suspect they were able to add an electric motor without changing much.

        1. The old machines had a large (for the size of the machine) flywheel that was also the gear the treddle was connected to. Between the large cast iron foot wheel, and the smaller gear on the machine, they could continue placing stitches even if you stopped pedaling for a second or two.

          Just remove that small gear from the machine, and clamp on a small electric motor with a foot control.

          Grew up with a treadle table holding up the microwave. And another is sitting in storage somewhere. I just haven’t found a machine in good enough condition to justify moving a large cast iron table out of my parent’s house.

  7. RIght out of high school I worked for a small, now long-defunct mom/pop electronics distributor.

    One day an ol’ boy comes in to buy a dial bulb for his portable AM/FM radio that “brought him luck” when fishing. He bought a box of (10) #123 lamps.

    30 minutes later he’s back to buy (6) D-sized batteries – “wasn’t the bulb”, he said.

    The next day, he storms back in – this time with the radio – yelling at us for selling him blown bulbs and dead batteries. He couldn’t see the dial to change the station during the previous night’s fishing.

    A few co-workers crowded around the counter to see what was going on. After 10 minutes I walked over while everyone was looking inside the radio for an issue, checking batteries, etc.

    I immediately noticed the knob on the top that said “DIMMER” in very faded letters. A little twist and boy, was he embarrassed. He kept the (clearly) unneeded lamps and batteries for giving us a hard time.

  8. I have a Honeywell evohome smart thermosthat, which has electronic radiator knobs. I have two radiators in my living room, being one “zone” and you can change temperature on the central unit or via the app, but also by turning the radiator knob (which is just a rotary encoder). Normally, if you set one radiator knobs to a high temperature, it will open it’s valve but also signal other radiators in that zone to open itself.

    One evening, I had problems with the heat exchanger in the flat, and wanted to test that and switched the radiator knob up to 26. I saw the heat exchanger started to flow, then turned down the knob back to 19 or so and heard the heat exchanger shut off it’s valve. I went into another room and came back a half hour later to a very hot living room, and everything set to 26°C. So I turned down the radiator, went away and came back finding it still hot.
    Then I turned it down again, watched it, and found that after 20 or so seconds it would be back at 26° again.

    After a lot of troubleshooting, I found out that the other radiator knob (which I had earlier set to 26°C), as soon as it recieved a lower temperature setting, was shutting down as soon as it’s motor started turning to turn off the valve, then reset, remembered it was set to 26°C (a useful feature if you want to protect your house against freezing) and sent all the other stations a 26°C signal. Then whenever you set another station to lower, this would repeat.

    I first thought the batteries were empty, and new batteries seemed to do the trick for a few days but would also sometimes fail (though no longer at 26°C) but then it would hiccup again.
    In the end I found out that the battery terminals were bent out and had so little springiness, that the motor (which induced a small torque in the whole unit) just momentarily mad no more battery contact and reset the electronics. I bent the contacts and had no more problems with this radiator knob.

  9. Diablo printers were developed by the Singer sewing machine company. But unlike Juki, Singer didn’t see a purpose for the project so the team that developed the HyType (they claimed it wasn’t short for Hyper Typer) took off on their own and founded the Diablo company to manufacture daisy wheel printers. Next was the HyType II, followed by the Diablo 630. All three were available with a wide range of options, including a keyboard so they could be used as typewriters.

  10. Back in the 1970s when I was a boy my mother had a sewing machine with the motor bolted to the outside of the housing. If the belt had come off, it would have been immediately obvious, and it could have been replaced in a few seconds. Such is Progress.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.