Elna SP foot pedal went bang

Elna SP foot pedal to the metal

On the back of a previous article about a repair I did on the rather wonderful Elna SP sewing machine, a reader got in touch.  She was a genuine sewing aficionado and had several top of the range current machines, but she used the trusty Elna SP for many smaller jobs, where the other machines didn’t quite cut it.

All Elna SP machines are getting on a bit and parts are either re-manufactured, scarce or secondhand, if you can find them.  Having said all that, a well-maintained Elna will run for many years and last much longer than new metal on sale now.

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FixItWorkshop, Worthing, November’18, Elna SP Special, in action

The foot pedal on this machine had gone pop, bang, finito.  It smelled terminal.

Knowing that parts for this machine are rarer than hens teeth and I do like a challenge, I took on the job.  I’m based in Worthing, West Sussex and the machine was located in Scotland, so after a short wait, the knackered pedal arrived in the post.

The pedal is held together with four small self-tapping screws and came apart easily.  The reason for failure was two-fold.  The copper leaf contacts had arced excessively and caused major pitting in the contact strip (see slide show) and the probably ensuing resistance had caused the main resistor to overheat, causing the winding to fail.

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The contact surfaces were easy-ish to fix, or rather breathe new life into as all they needed was cleaning and re-shaping.  The resistor was a bit trickier to mend.  Getting hold of a replacement was going to be near impossible, so the only thing to do was to try and repair it.  Without that particular style of resistor, of that value, it wouldn’t work again.  Luckily, there was some excess resistance wire on the thing and I managed to twist it in to the broken section.  Soldering was not an option, since the wire was an alloy that wouldn’t take to solder and in any case, these things get hot in normal service.  I twisted both ends of the break to form a new section, while maintaining the same length of windings on the resistor, essential if I was to match or get close to the original specification.  Difficult.  Luckily, after a few goes, I managed it and the applied a little heat-conducting (and therefore dissipating) paste to the join.

With the pedal reassembled, I was only able to test it with my meter, since the sewing machine was far too heavy to post.  The pedal tested as a closed circuit (OK), which was a result.  I then had to wait for the pedal to be collected, taken back to Scotland and tested.  Fortunately, my fix worked and the machine sprang in to life, without a hitch or missed stitch.

Now, a word of caution with this one.  This is NOT the best way of mending something like this and all I’ve probably done is prolong it’s life a little longer.  There are generic sewing machine pedals that would work with this machine and will be fine, when this one fails in future, but that’s not the point.  The main thing is that something that was broken is now working and even if it’s not the best fix, at least it will run for a bit longer.  Happy days.

Cost of replacement: (generic part) £15-30.  Cost of repair, my time, a bit of solder and several cups of tea.

Very quiet Bauhn DAB Radio from Aldi

A little DAB radio, repaired at the workshop.

A colleague of mine brought this cool little DAB radio in to the workshop as it’s once crisp DAB tones were now no more and all life from the little device, had seemed to have ceased.  It was, very much, a dead radio.  When working, it picked up every station available, really clearly and seemed to out-perform the much more expensive devices my colleague also owned.  However, after a few months in the hands of his son, the radio would no longer turn on when plugged in.

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FixItWorkshop, May’18, Aldi Bauhn Radio, in for repair.

It was brought from Aldi for under £10, which seemed like a bit of a bargain to me.  It’s amazing just how much DAB radios have fallen in price in the last 5 years or so.

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FixItWorkshop, May’18, Aldi Bauhn Radio, in for repair, back of the radio.

The Bauhn UDABR-0197 (catchy name) is a compact, portable radio and is capable of being used with either a plug-in adaptor (supplied) or 4 x ‘AA’ batteries.  When powering this radio using either plug-in adaptor or batteries, the little radio refused to do anything.  Very sad.

I always start with the basics, so I checked the power from the plug-in adaptor first, which seemed to be delivering its 5.9VDC, pretty much spot-on. As a side note, I always check the condition of plug-in adaptor leads and plugs as they seem to almost always be made of the thinnest wire available in the Far East and prone to cracking causing poor connections.  This one was fine.

Opening up the radio was really easy, just 4 cross-head screws and the two halves of the radio came apart without any major dramas.

The first thing you notice about (cheaper) small appliances like this, is the ‘lack’ of anything inside.  The circuit boards in new small devices can sometimes be multi layered affairs, using micro components, making repair with normal workshop tools very difficult or impossible.

Luckily for this little radio, the designers have had the foresight to keep the power distribution board separate from the main ‘radio’ gubbins and this seemed to be of conventional construction.

On closer inspection of the power distribution board, it revealed a break in two of the pins from the ‘power-in’ jack socket meaning that power would not get through to the main circuit board.  The two pins were also shorting together, causing a local loop connection.  This meant than neither mains adaptor supply nor battery would power the radio.  Problem realised.

I was then able re-make the connection using a soldering iron on the board, reconnecting the pins to a spare section of copper detail on the power distribution printed circuit board.  Very satisfying.

Once the radio was back together, all screws back in place, power supply connected, the radio burst in to life, just in time for me to listen to my favourite station.  Happy days.

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FixItWorkshop, May’18, Aldi Bauhn Radio, in for repair, all fixed.

Cost of a new radio; £10.  Cost of repair; A bit of soldering and a cuppa plus gingernut biscuit.