Wired for sound: AKG Headphones repaired

A pair of decent studio headphones dodges the bin…

Headphones are big business and global sales of these devices reach over $500m per year in the U.S. alone (quick Google search, so it must be right eh). As I’m sure you do; When I read sales figures like that, I wonder what the average life expectancy of headphones is, as I’m sure that many sets are viewed as disposable items.

Bluetooth and other wireless headphones aside, most wired headphones are fairly straightforward to mend, assuming no damage has been done to the speaker or ‘phones’ part. You just need basic tools, some patience and a fair bit of nerve… See how I got on with this pair of AKG K92s.

Make and model: AKG Headphones K92

Fault reported: No left channel

Cost of replacement: £35 when new

Manufacturer support:  0/10

Cost of parts: £0.00

My repair time: 45 mins

Tools needed: Soldering iron, small screwdrivers

Sundry items: Insulation tape, holt melt glue

Cleaning materials: N/A

Repair difficulty: 4/10

Cups of tea: 1

Biscuits: No biscuits this time, as it was lunchtime. It was cheese on toast for me, with some chorizo on top as I seem to remember, maybe a dash, just a tad, of tomato sauce- from Lidl I think…

I’d just finished the last mouthful of tea, I was getting peckish, thinking about putting the grill on, when a neighbour of mine rang the doorbell, at lunchtime -of all times.

The conversation went like this; Matt, could you have look at these old headphones for me? I was about to chuck them out and I know you like playing with old stuff like this. They used to be good, but they only work ‘one side’ now. I mean, they’ve probably had it. …Hang on I said, let me have a look, leave it with me. Famous last words.

I was quite flattered actually, as I really do like receiving work this way. When there’s little hope for something that’s probably on its way to the great scrap bin in the sky, I must admit that I especially like taking on that challenge of making something work again. Diverting the once condemned item back into full service is the thing that keeps me motivated.

On with the repair. The fault reported was ‘no sound from the left speaker’. The first thing to check with anything corded is the cord/ flex/ wire itself. While a visual check of a wire is no conclusive way of proving that it works or not, tell-tale signs of bending and chaffing can save a lot of time elsewhere. Rule out anything silly before wielding screwdrivers, I say.

Since the wire looked OK and the plug wasn’t bent, it was time to take the headphones apart. The AKG K92 headphones are simple to dismantle; just pull-off the headphone covers and the speakers are held together with just four small cross head screws, each side.

Using a multimeter set to continuity test, I was able to prove each part of the cable. The main wire from plug to headphone set proved OK, which was a good thing as it meant no replacement required (these are widely available on eBay). The headphones’ over the head band, as well as keeping things snug on ones’ noggin, also carries the signal from one side of the set to the other. If you’re still reading, I hope that makes sense. Anyway, the meter proved that it was all fine.

FixItWorkshop, Worthing, AKG K92 headphones, left channel re-wiring.

In the end, the fault lay with the main wire to headphone speaker on the left side. To be honest, I should have checked that first as that connection is always under load as it crosses a pivot point, allowing a few degrees of movement and therefore comfort for the user.

On the subject of comfort, while doing the repair, I noticed that the headband was a little torn at each end, presumably a result from many intense sonic moments. The vinyl coated band was a tricky customer to repair, but a little hot melt glue along the torn edges, soon fixed things, giving the headphones a fresh feel.

A quick remake of the connection (cut cable, re-solder) and full hi-fi was restored and the headphones were ready to blast again. Turn it up to 11.

A bit of 70’s fun: Sona J996 Coffee Percolator

An office find, escapes the scrap yard.

Despite the 1970’s kitsch-ness of the electric percolator, they are very good at making coffee and the delightful coffee smell you get when brewing-up is sublime.  Here’s an advert from the time.

Top tips for keeping your coffee percolator in good order:

  • Descale using a kettle descaling solution as needed
  • Keep the coffee strainer clear of debris
  • Make sure the lid always fits between the strainer and the percolator body

A colleague found this percolator while clearing out an abandoned office cupboard.  I suspect that this one might have been bought as a wedding present way back and had ended up in the office when someone had decided play the role of barista at work.

It was missing its power lead and was headed for the recycle bin, when I intervened.

The power lead needed was an obsolete design used on British appliances of the era and was similar in design to the more modern and current, IEC C13 or ‘kettle lead’.  However, modern kettle leads did not fit this percolator.

More drastic action was needed.  Luckily, I had an old appliance I no longer needed, so I scavenged a board mounted IEC C13 socket from it and replaced the one originally fitted.

After some soldering and a bit of jiggery-pokery, this Sona Percolator now brews coffee using an up-to-date power lead.

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Cost of replacement:  £40.  Cost of upgrade: £0.

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.

Intermittent Einhell E-BH 950 SDS drill

Poorly drill repaired at FixItWorkshop

The owner of this drill complained that it work perfectly one minute and then stopped the next.  It was making DIY a very slow process.

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FixItWorkshop, April’17, Worthing, Einhell E-BH 950 SDS drill repaired

As this was a cut-out problem rather than a slowing down issue, power problems were a likely suspect.

On test, the cable flex near the base of the handle seemed to be the issue as giving it a good wiggle seemed to reproduce the fault.

Opening up the drill (several self-tapping screws) revealed a fairly straightforward layout with cord, mechanical connector, smoothing circuit (mains splash) and switch.  Having suspected the culprit to be cable flex near the handle, I cut the cable down and re-made the connection, removing the suspect part of the cable.

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FixItWorkshop, April’17, connector shown

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FixItWorkshop, April’17, broken cable removed

Despite cutting the cable flex down by about 8″, the owner was pleased with this fix since no spare parts were required and no real issues will be noticed since it will be mainly used with an extension lead.