I have a halogen light [ikea brasa 360] where the plug/transformer is missing. Image here https://i.stack.imgur.com/GMoWa.jpg I did a bit of research and figured I could cut the cable and solder the wire to that of a plug/transformer rated at 12v. When i cut the cable on the lamp i found three wires red, yellow and blue. Given that teh transformer [from a hard drive] had only two wires I went through them all two at a time until i got a light. I joined them [yellow and blue] and the light lit but it flickers at a steady throb now and doesn't light properly. Can anyone advise as to what i need to do. As you can tell I am far from an expert in these matters. Any help would be gratefully accepted. Thanks

  • What is the red wire connected to then?
    – topshot
    Oct 6, 2016 at 14:22
  • If it's a reading light, I'd be inclined to just replace the whole unit (maybe keep the bulb - if you buy from Ikea, the bulbs aren't always included)
    – PeteCon
    Oct 6, 2016 at 18:48

2 Answers 2


You have probably replaced a regulated power supply (this creates a constant 12V) with an unregulated one (which supplies 12V on average, but the actual level fluctuates). Or the power rating of the new transformer is too low.

You need a regulated power supply that can supply not just the right voltage (V) but also enough power (W).


Looking at the adapter in the photo, it shows 9.6V / 11.5V ~ .
This shows a AC output on the adapter with two voltage ranges.
Not knowing which lamp you have and if it has a high low setting, but based on the three wires and the adapter it looks like you need a dual voltage AC output adapter. Then all three wires will be used and the lamp will function proper if it has nothing wrong with it.

  • Thanks you very much for the suggestion and help. I'll try and track one down but from what i can see the ones i find online have two wires and not three. amazon.com/AspenTek-60watts-Voltage-Waterproof-Transformer/dp/… The lamp does have three setting, off, high and low. If i am not being too much of a pest could you give me an example of the type I need. Thanks in advance.
    – Jean
    Oct 7, 2016 at 11:47
  • I would take a tour of your local thrift stores (goodwills and such if you have them). Look for a power pack that shows output values in the range of 9VAC to 12VAC. Finding a dual voltage version will be vary unlikely, but the 12VAC output ones I have seen quite often in the thrifts for 2-3 dollars. If you do find a 12VAC and have some electronics understanding it is possible to add a resistor in for the third wire as a dropping device for a low light position. Oct 7, 2016 at 13:42

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