Alesis (DM Lite) Drum kit without kick

Alesis Drum Kit gets a cheap repair.

A neighbour of mine is a talented musician in a local band and also teaches school children various instruments.  Some of his students learn the drums, which is most parent’s nightmare as any notion of a peaceful evening is shattered.  Luckily, electronic drum kits are an excellent way to learn with headphones, while keeping happy parents and neighbours.

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FixItWorkshop, Worthing, November’18, Alesis DM Lite Electronic Drum Kit
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FixItWorkshop,  Worthing, November’18, Alexis DM Lite main drum module

This kit was missing several beats and was hampering learning, so time for a visit to the workshop.  I’m no musical instrument repair specialist, but I thought that the drum kit must use electrical contacts, switches and rudimentary electrical components and I was right.

Two faults were reported; The kick/ foot pedal was intermittently not working and one of the drum pads was hardly working at all, unless you hit it with a sledge-hammer.  Time to see what was going wrong.

First up was the faulty drum pad.  Opening up the back of the pad was simplicity itself, just a few screws held the back to the pad.  Sandwiched between two halves was a sensor, a bit like a piezo flat speaker, similar to the type found in many toys with sounds.  I guess the principle here is that vibration detected by the piezo sensor is converted to analogue variable voltages by the drum kit’s circuitry.  While apart, I noticed that some of the copper detail tracks on the printed circuit board which had a standard 3.5mm jack socket (to allow a connection back to the rest of the kit) had cracked.  Looking again through my magnifying glass revealed quite a bit of damage, probably as a result of many Keith Moon wannabes.  Testing these tracks with my meter confirmed an intermittent fault, so out with the soldering iron, to repair the connection.  Plugging the pad back in, it was ready once again for more drum solos.

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Next up was the dodgy kick/foot pedal.  As the with the drum pad, the pedal would cut out intermittently.  A few screws held the pedal together, so only basic tools required.  See the slide show below for an idea of the construction.

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The fault with the pedal was similar to the drum pad.  Some of the copper detailing around the 3.5mm jack socket had failed and required some careful soldering.  I say careful, as applying too much heat at once would, likely as not, melt the casing of the socket.  One had to take care.

Once soldered, the pedal was much better.  I didn’t get a full 10/10 repair with the pedal since I think there was wear on the kick sensor, but it was an improvement none the less.

Cost of replacement:  £lots.  Cost of repair, my time, two cups of tea and some solder.

 

 

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.

Lucky Voice Microphone without the X-Factor

Lucky Voice Microphone repaired.

A colleague of mine came in with a broken microphone, which is part of a Lucky Voice karaoke set and retails for about £60.00 on Amazon.  The microphone had worked pretty well, but recently had lost its ‘X-Factor’ somewhat.

The microphone is fairly standard fare and connects to a standard XLR plug and socket arrangement.  As this part is usually under the most stress as the singer moves about, it seemed sensible to have a look at that first.  Upon connection to my amp, there was a huge amount of crackling which seemed to coincide with cable movements at the microphone end.  Swapping the lead for a known good one I had proved that the microphone was fine, but the lead not so fine.

Only one screw holds the plug together and straightaway, the problem presented itself.

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FixItWorkshop, Oct’17, X-Factor microphone, XLR connector.

The main core had detached from the connector, as the outer cable sheathing has come away from the XLR connector body clamp.  Not ideal.

A quick strip back and solder job and the wires were connected back where they needed to be.  A little dab of hot-melt glue on the cable grip and a re-tighten and the cable was not going to move anyway.

With the plug re-assembled and the screw put back, the microphone tested perfectly on the amp, ready for karaoke once more.

Cost of a new similar lead: £10,  Cost of repair: 15 minutes, dab of glue and solder.  Nice.

Testing, testing, 1-2-what?

My Fairlady sings again…

When my wife isn’t looking after our daughter, she sings part-time in and around Sussex and uses a simple portable microphone and amplifier set for gigs. The amp and the rest of the kit lead a hard life, being transported between the car boot and venue and on one occasion, the microphone was dropped from a height.  I guess things could have been worse, it could have been the amp!

The microphone now rattled badly and seemed to cut out when connected up, even when turned up to 11.  Not a good sound when she was in the middle of ‘Moon River’.

The microphone actually came from a Lidl karaoke set and is made by Silvercrest, a Lidl brand.  It’s a heavy, metal bodied microphone with a decent quality feel and metal grilled top.

The rattle seemed to coincide with the cutting out, so it seemed sensible to open up the mic.  Three Phillips screws hold the casing together and upon opening it up, the problem quickly became apparent.  The metal weight inside had come away from the inside of the casing and was occasionally ‘shorting’ the connections on the back of the on/off switch.  Not good.

While in bits, I checked all the wiring for continuity, no problems there and decided to clean the switch with contact cleaner for good measure.  Once all the electrical side of the mic was proved, I reassembled the casing with the parts, adding a little hot-melt glue to the metal weight to prevent it coming in to contact with the back of the on/off switch.

This wasn’t the end of the song (sorry).

Upon hooking the mic up to the amp, it now worked again without cutting out, but I couldn’t help but notice that the lead connecting to the base of the mic seemed to be causing a slight crackle.  Not a nice sound effect.

Opening up the three-pin mic connector revealed a simple design, three poles soldered to the microphone’s wiring, one core and one screen.  A quick cut, strip and re-solder and the lead was ready to roll once again.  Before I did the cable crimp back up, I added another dab of hot melt glue between the cable outer and flex guard, to ensure the cable couldn’t twist, which might cause the connector to fail again.

Cost of a new microphone £20+.  Cost of repair; Time plus soldering and a bit of glue.

‘My Fairlady’ sings again…

 

 

 

 

Cheap Tesco DVD player

This cheap and quite frankly nasty DVD player came in as a dud unit.  No lights on, nothing.  To be frank, not even I thought it would cost in to repair it, since the owner told me it didn’t cost more than £20 in the first place.

Never mind, off with the cover and a quick poke around with the multi-meter revealed no power coming from the transformer within the unit.  This converts high voltage from the mains to lower, safer voltages for the player.  On this DVD player and many others I’m sure, the internal processes are broken up in to ‘cards’.  On this unit, there’s a power card, a logic card for the motor drive and a video card for the picture.  Closer inspection of the (cheap and horrible) power card revealed several faulty components, which had failed catastrophically.  At first glance, I suspected that the cost of replacing individual components wouldn’t cost in and that sadly, this DVD player might be headed for the bin.

Fear not!  With the power of Amazon, I was able to find a generic suitable DVD power card via China that fitted, with a small amount of wiring for £5, delivered.  Job done.

Here’s a video of the fix.