Touch control lamp repair

An old lamp sees the light…

You’ve got to be in the mood for certain repair work.

A friend of ours dropped in a ‘dead lamp’ to the workshop with a message:  “Matt, can you mend it”?  I then sort of forgot about it for er, nine months.  Whoops.  I need to focus on the workshop more.

The lamp was much loved by its owner and its current lack of light was leaving her in the dark.

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FixItWorkshop, Worthing, May’20, Endon Touch Control Dimmable Lamp.

Make and model: Endon Touch Control Dimmable Lamp

Fault reported: Not working

Cost of replacement: £30ish

Manufacturer support:  0/10

Cost of parts: £3 approx.

Hours spent on repair: 30 minutes

Tools needed: Screwdrivers, test meter etc

Sundry items: None

Repair difficulty: 2/10

Cups of tea: 1

Biscuits: Wagon Wheel (Jammie)

These touch lamps were a bit of a novelty back in the day and seem to have fallen out of favour in recent times.  However, the owner of this one was a bit upset when suddenly one day, it wouldn’t work.

When working on anything mains operated, I always start with the basics:

  • Is the bulb working? Yes.
  • Is the mains flex OK?  Again, yes
  • Is the fuse (UK) intact? All OK

Lamps like this are pretty simple; there’s a mains wire, there’s a bulb and holder, a switch and the main lamp unit itself.  Some dimmable lamps, like this one, feature an electronic dimming module, which in this case was built into the base of the unit.

First step:  Remove the base cover

Removing the cover was fairly straightforward and only involved a few self-tapping screws, under the felt pad base.  This exposed the dimmer module, which when tested with the meter, was not outputting any current to the lamp circuit.

Second step: Dismantle the dimmer

Dimmer modules like this are not designed to be repaired and contain no user-serviceable parts (don’t get me started on that!).  But in the past, I’ve had some luck cleaning components and re-heating the odd dry joint with a soldering iron.  In this case, it was no joy.  A replacement module was needed.

Third step:  Find a new dimmer!

I can’t remember what I used to do before finding specialist electronic suppliers on eBay and alike.  Oh yes, I just remembered:  I struggled!

It didn’t take long to find a new (almost identical) dimmer module on eBay for about £3, delivered.  How do they do it for the money?

After 2 weeks of waiting, the new module arrived in the post, hand delivered by our usual friendly posty, Keith.

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Forth step:  Fitting the new module and test

Comparing the dimmers side-by-side revealed that they were more or less the same, using the same wire colours…but in a different combination.  This meant that it wasn’t a simple ‘cut and re-join’ the new dimmer to the existing wiring.  Oh no, it meant cutting everything out and starting again.  Still, with only four wires, it didn’t take long.  With a little soldering and heat shrink, one would never know I had been tinkering.

A good job, jobbed, even if it did take me months to get ‘aroundtuit’.

Quite literally illuminating.

 

Magic Lamp

Rub the lamp release the genie, make three wishes (make ’em good)

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FixItWorkshop, Worthing, March’20, Dimmable Projector Lamp

I’d say that 8 out of 10 repairs commissioned by folk who get in touch are for sentimental reasons.  Take this unusual lamp.  It’s not worth a great deal of cash, it doesn’t use the latest luminescence technology and it doesn’t even have a makers’ mark (we think it came from Aldi or Lidl).

Yet, it had been a family favourite for years and the owners were keen to see it light their world, once more.

Make and model: Dimmable ‘projector ball’ lamp

Fault reported: Not working

Cost of replacement: £30ish

Manufacturer support:  0/10

Cost of parts: £15.30 plus £3.25 for bulb

Hours spent on repair: 1 hour

Tools needed: Spanner, screwdrivers, test meter etc

Sundry items: None

Repair difficulty: 2/10

Cups of tea: 2

Biscuits: 1 Gold Bar

Firstly, we all make mistakes and here’s one of mine!

It’s easy to fall into traps or ‘snap diagnosis’ when doing a repair and I want to share a ‘little accident’ that I had with this one.  Even an experienced repair bloke can make mistakes.

Here goes.

After checking the mains plug (all fine) and cable to the lamp for continuity and potential shorts to earth, I was convinced that the supply lead was fine.  All good so far.

Next, I checked continuity from the dimmer module to the lamp socket.  Ah ha, that’s the problem, that link in the circuit is dead.  A quick repair job, on to the next?  Not quite.

As a temporary test, I decided to by-pass the dimmer and rig a temporary wire to the lamp, to prove the wiring was OK and that the dimmer was the fault.  Upon plugging the mains plug in, the bulb nearly exploded.  Bang!  My safety circuit breakers then stopped the power to the whole workshop.  I was now in darkness, but luckily, my heart was still ticking.

I had failed to realise that the dimmer on this light was actually doing two jobs; dimming the lamp as well as stepping down from the (UK) mains 240VAC supply to a safer 12VAC operating power.  I had connected 240 Volts to a 12 Volt bulb!  What a simple mistake to make.  If I had simply inspected the dimmer more closely, I would have realised this.  The original sticker and badges on this lamp had long disappeared.  An important lesson, relearned.  Time for a cup of tea and a biscuit.

The repair.

With the power back on, it was time to see what the original dimmer was doing.  Not much as it turned out and due to the tininess of the dimmer’s components and build type, I was unable to say why it had failed.  I suspect that one of the power sink control components (maybe a Zenner diode) had failed, causing an overload to the onboard one-time blow fuse.  However, that’s just an unproven theory.  The fact was that I now needed a replacement dimmer with step-down 240/12VAC capability.

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It turns out that only a couple of manufacturers make such a dimmer module and I chose one made by Relco as it seemed to match the original specification quite well.  It would have been tempting to convert the lamp to mains power and just fit a simple on/off switch, but I’m not keen on this as technically, the lamp would need to be re-subjected to British/ EN Standards, not something I was prepared to do.  Unless impossible otherwise, all kit leaving the workshop must be original specification or better.

With a new (correct) dimmer wired-in and replacement MR11 bulb fitted, the lamp came to life once more.  I’d also fitted a proper mains on/off switch, since the replacement dimmer did not have one.  The new switch would isolate the flow of power to the whole thing when not in use, hopefully prolonging the life of the dimmer module.

The owners of this lamp were very pleased to have it back as they had missed the lovely light patterns it projected on to their ceiling.