underlighting problem

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MrChips

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My kitchen units have low voltage underlighting (installed about 7 years ago) controlled by a touch-sensor/dimmer. Lately they have started to behave strangely - about 10 to 20 minutes after they have been switched on they start dimming and brightening on their own (as if someone were pressing the sensor continuously).

Is this likely to require a new sensor, or a new transformer - or might it just be a contact fault in one of the lights?

Any suggestions appreciated.

 

Mr Sworld

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My kitchen units have low voltage underlighting (installed about 7 years ago) controlled by a touch-sensor/dimmer. Lately they have started to behave strangely - about 10 to 20 minutes after they have been switched on they start dimming and brightening on their own (as if someone were pressing the sensor continuously).Is this likely to require a new sensor, or a new transformer - or might it just be a contact fault in one of the lights?

Any suggestions appreciated.
It would suggest that the dimmer/sensor is up the spout mate. The lamps and transformer would not cause this sort of fault (assuming that the transformers are designed for dimming). :)

 

MrChips

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Thanks for the idea Mr Sworld. When I came to disconnect the sensor/dimmer I found that the white casing of the transformer has a brown patch (suggesting overheating?) around the spot marked "TC" (thermal cutout?). Maybe there is a problem with one of the lights? I am going to try running the kit with each light disconnected in turn.

 

Mr Sworld

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How many lights are on the circuit and what wattage are they? Do you know what the power rating of the sensor is?

If the area around the Thermal Cutout is brown then you are either getting an overheating problem or the plastic has discoloured with the heat over 7 years. I would think that if the cutout is operating then the lights would simply switch off rather than dim down.

 
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My kitchen units have low voltage underlighting (installed about 7 years ago) controlled by a touch-sensor/dimmer. Lately they have started to behave strangely - about 10 to 20 minutes after they have been switched on they start dimming and brightening on their own (as if someone were pressing the sensor continuously).Is this likely to require a new sensor, or a new transformer - or might it just be a contact fault in one of the lights?

Any suggestions appreciated.
GHOSTS! :eek: :O] :) ]:) ; \

sorry... Hello MrChips

just wanted to say welcome to the forum..

looks like Mr S it providing a bit a sensible guidance..

so listen to him and ignore me...

I'll just sit here and eat much lunch quietly:|PrayBlushing:z

 

MrChips

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How many lights are on the circuit and what wattage are they? Do you know what the power rating of the sensor is?.
Four lights - 12V, 20W.

When I ran the kit with only 3 lights connected it lasted over an hour before going into "ghost" mode, at which point the transformer was almost too hot to touch.

I'm not sure that the sensor has a power rating - it is a single wire device so (I assume) has no current running through it, although I can read on its mounting "250V 1A" - does that make any sense?

I'm trying it with 2 lights connected now; also googling for the part number on the transformer, which is of German origin.

Thanks again.

 

Mr Sworld

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Four lights - 12V, 20W.When I ran the kit with only 3 lights connected it lasted over an hour before going into "ghost" mode, at which point the transformer was almost too hot to touch.
Okay so that's just 80 Watts

I'm not sure that the sensor has a power rating - it is a single wire device so (I assume) has no current running through it, although I can read on its mounting "250V 1A" - does that make any sense?
So the touch dimmer is rated at 250 Watts, more than enough for the job.

I'm trying it with 2 lights connected now; also googling for the part number on the transformer, which is of German origin.Thanks again.
Now there could be a problem with a transformer. Have a look and see if any of them show signs of overheating or, as you are doing, disconnect all but one of them and see if the problem re-occurs as you add each one back onto the circuit.

To be honest I think your dimmer has just reached then end of its life. It is obviously an electronic dimmer rather than the more robust resistance dimmer. You are going to have to bite the bullet and buy a new one I'm afraid.

Here are some.

 
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Did I get the correct impression that there is only ONE transformer?

This could be causing an issue. The touch dimmers, as i recall, rely on the load for correct operation. If the tx is faulty (too hot to touch=BAD), then I`d want to change it anyway. It shouldn`t be getting that hot, and may be contributing to the problem with the dimmer.

KME

 

MrChips

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One transformer with it's SEC connected to a harness allowing connection to 6 outputs. I have 4 connected.

The transformer is rated on the SEC side as 12V 5A so I think I have been overloading it. I must have substituted 20W for 10W bulbs at some stage.

The dimmer is simply a metal plate connected by one wire to the "dimmer" terminal on the transformer.

I think I need a new transformer - but cannot trace the original through google.

By the way, thanks for the links Mr Sworld but I think they are for a different kind of dimmer.

 

Mr Sworld

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One transformer with it's SEC connected to a harness allowing connection to 6 outputs. I have 4 connected.The transformer is rated on the SEC side as 12V 5A so I think I have been overloading it. I must have substituted 20W for 10W bulbs at some stage.

The dimmer is simply a metal plate connected by one wire to the "dimmer" terminal on the transformer.

I think I need a new transformer - but cannot trace the original through google.

By the way, thanks for the links Mr Sworld but I think they are for a different kind of dimmer.
Yes it seems that way. I was under the impression that these were 'standard' transformers with a dimmer on a 230V supply. However this is obviously a proprietary system that I've not seen before.

So I'm going to have to bow out of this one now. :(

 

MR DIAZ

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Hi Mr Chip i would suggest that the sensor/dimming switch be temporarily bypass to prove the lighting is not malfunctioning.

As it sounds by the way you have explained it, that the sensor is most certainly the problem.

Also call a local sparks to revise the lighting itself and to make any modifications the units need.

 

MrChips

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Thanks for all your helpful replies. My googling eventually came up with a very helpful technical advisor at a wholesale lighting firm. I have ordered what looks like a functionally similar transformer (but with a higher power rating). I'll report back when I have got it in place. Meanwhile the existing set is working adequately with only two lights connected.

 

MrChips

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The new transformer is in place and working perfectly...so far. For reference, it is labelled "LL MODEL SET 105-D"

 

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