Repair: Mezzo ESM-008 Sewing Machine Power Jack Assembly

Sometimes, the best thing in life is not knowing what might happen next. After I repaired a washing machine using some rather funny trickery, this week, it was the sewing machine that needed attention. The particular sewing machine was a Mezzo branded ESM-008, an Aldi special.

Judging from the label, it would have been on sale in May 2006, making it almost 12 years old. But what is the failure?

Diagnosis

The patient looked okay from the front at first glance, but the problem very quickly revealed itself. Like a patient with a dislocated arm …

… this one had a dislocated socket. Namely, the panel which is involved in the power/pedal input and power switch had somehow popped out of the case entirely. A fracture in the plastic can be seen, which isn’t a great sign.

But it gets worse. With this failure, the rear portion containing exposed live contacts can be touched. I’m sure that this machine might have continued to be used if it were not for the fact that the live wire for either the motor or something else had broken out from a terminal, leaving the ring lug behind.

Repair

I suppose the good news is that the rest of the machine was mechanically sound, so there was no need for me to be concerned. First step is to get into it and get a closer look at how the assembly was supposed to be put together.

To do that, one screw can be undone from the underside to release the side panel entirely.

Inside, we see that the arrangement is like a junction box or even a hobby case. There would have been two screws securing the front portion to the rear plate, and the other two screws (visible) to secure the rear plate to the frame of the unit. It seems that the plastic they used might have been too brittle, the screws may have been overtightened causing plastic cracking or the plug may have been too forcefully pulled/pushed to cause this type of failure.

However, this does mean that there are probably loose plastic parts and screws inside the machine, so I decided to first dismount the plastic plate and the screws and then give the machine a good shakedown. While some loose plastic was dislodged, the screws I expected to find were nowhere in sight. Maybe they got lodged somewhere inside or have been long lost.

Putting the two halves together, we can see that the original eyelet for a screw/bolt has snapped, thus a different solution is required. I decided to use superglue (cyanoacrylate) as it was to hand and fairly strong, but I decided that this shouldn’t just be the only method of securing the front half.

To attend to the wire, I grabbed a section of heatshrink and used a pair of needle-nosed pliers to undo the brass nut and separate the remaining lug. I cleared off the old heatshrink off the lug and cut the new piece to “just” fit while not obstructing the joint.

As the lug was once crimped, and I have no faith in a “loose” brass crimp onto copper, I decided to solder the joint for both mechanical and electrical reasons. The heatshrink was a little short so that I could solder the lug, but in doing so, it had already shrunk over the wire due to conducted heat.

I decided to add a second layer of larger heatshrink that could go over the lug just to be safe. However, I should have probably reduced the overhang slightly to ensure even pressure all-around the brass lug. I don’t think it’s critical due to the magnitude of the current involved and the tension on the nut.

There it is, reassembled into the terminal block.

After running a bead of superglue all around the flat surfaces and pushing together for a good hold, I decided to wrap electrical tape around the two halves in the area that would not interfere with its function. By doing this, if the case halves did come apart, the tension in the tape should stop the whole thing “flopping” out immediately, giving some time for a proper reaction. The tape was a little wide, so I had to use a knife to clear out the lower power plug port.

Once reinstalled into the machine, it fits just fine with the cables tucked neatly underneath.

The final step was to reinstall the side panel and test. The machine worked just fine, as I sewed a piece of paper together, so I would call it a success.

Conclusion

This wasn’t a very complicated repair, but it is a little shocking as to how the design could easily result in live parts become exposed (e.g. tripping on the power input lead a few times might do it). Once damaged, the plastic ears on the jack panel fractured, making a perfect repair impossible. Glue will probably suffice to give the machine a little more life, but whether it is sufficient in the long run given the stresses is something that I’m not certain of. In some sense, this issue might have been reduced if the side panel cut out was smaller than the jack panel or the jacks integrated into the side panel, thus providing some more substantial mechanical support.

But anything saved from the landfill and any purchase deferred is a win in my books.

About lui_gough

I'm a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!
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5 Responses to Repair: Mezzo ESM-008 Sewing Machine Power Jack Assembly

  1. darius says:

    Thank you Lui,

    excellent job done.
    In the past I have got 2 small size all plastic sewing machines and made efforts to turn them mobile with Li-Po battery power supply.

    Keep in mind the sticker’s memo:

    “Don’t immerse in water”

    BTW
    I start with my Open Fabrication Lab
    since I can provide 100+ used electric, electronic appliances, equipment, some faulty,
    which can be dismantled locally and third party developers, connected via Internet, can
    make suggestions on further improvements, reconstruction, putting Arduino remote control IoT
    and new features into old, used hardware.

    Living in EU I am lucky to get easy access to more than 1,000 used, faulty hardware items,
    which can be disassembled, rebuilt, upgraded, refurbished by interested parties.

    Since I am budget limited, have no plans to sent upgraded hardware, home appliaces abroad.

    I get my new Xiaomi smartphone soon to make a lot of images of my used, super hardware, home appliances with the intention to give them second life.

    I would greatly appreciate your opinion.

    greetings,
    darius

  2. darius says:

    BTW 1:
    My suggestion to your
    washing machine using some rather funny trickery
    http://goughlui.com/2018/03/08/repair-lg-wf-t552a-5-5kg-turbodrum-washing-machine/

    Personally, I would unscrew selenoids and replace by sides, leaving wiring intact.
    To get easy access to all 4 screws on both sides, I would remove the whole
    inlet solenoid unit from the washing machine, since it’s a spare part mentioned by you.

    greetings,
    darius

    • lui_gough says:

      That is one way – I did think of it but I didn’t want to disturb the inside of the unit in case the rubber inside has already started to disintegrate or I lose a small part (like a spring, etc). I guess it’s part of being more electrically minded than mechanically minded.

      – Gough

  3. Have you come across low heat thermally moldable plastic pellets yet? They seem to be available under a variety of brand names, such as ThermoMorph, Instamorph, etc. I’ve been using it for plastic repairs such as this recently. Hand moldable after being heated to 60C, and surprisingly strong once cooled back down.

    • lui_gough says:

      Actually, I haven’t. I suppose that’s because I rarely ever have the chance to look further than what I have at hand when it comes to repairs (i.e. less than an hour turnaround since the damage was only discovered when it was needed), but also, a lot of cool things just don’t make it to Australia (at a decent price, that is). Now that you mention it, I guess I’ll have to take a look :).

      – Gough

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