Dimmer defunct

Hi All

Hoping you can help me and and a mate who also is experiencing similar problems.
All was fine for 6-12 months.
Now we have rooms where the dimmers pretty much are defunct.
If they work, its only for a few seconds full light 100% then it automatically cuts to say 2% light (small orange tinge) Might flicker back to full but then go back to 2% levels and remain. Sometimes even no tinge at all.
Just seemed to have happened out of the blue.
Any thoughts on how to fix this, and in addition whether one can do it them selves or would require an electrician.

Any help is much appreciated.
Many thanks

Have you tried replacing the dimmer switch? What type of lighting are you trying to dim?

Nope, not tried replacing the dimmer switch.

I mean they worked fine for a year.
Do dimmer switches and their mechanics suddenly just break down?

The lights at my place are 4 halogen spot lights.
All 4 of the lights behave the same way, hence hang at 0% or 2% power with very slight itermittent 100% lightoutput.
My friend has a single regular bulb that behaves the same way.

Let me know if you feel I should try replace the dimmer switch.
If so, given I have 4 smallish ceiling halogen spot lights, is there a wattage related dimmer I need to consider, or merely one that handles the wiring for 4 lights?

All was well at first with these dimmers?

Did you change anything - brighter bulbs for example?

Did this start happening just after a bulb blew?

Yes, both our dimmers have worked.
I bought my place 10 months ago and my friend about 16 months ago.

I have never had to change my lights in that time, and for 9 months they worked fine.
I may have left my light on all day one time, which may have resulted in this behaviour. Not 100% sure of this, but vaguely remember doing something like that and then this problem soon afterwards.
But the dimmers definitely worked perfectly for a good period of time, with no issue at all. They started acting up and only a little at first. The issue seemed to get worse over time, going to a level where the light is unusable now.

My friend's situation is much the same. Worked for 15 months, with a replacement bulb being done once inbetween that time. Following the replacement of the new bulb worked for a few months fine and then started this erratic behaviour, which is now pretty much at rubbish levels of light. She tried changing the bulb again, yet same behaviour.

Are these new houses? Same builder? Just wondering if you've simply got cheapo switches that don't last long, or aren't designed for dimming halogens....

Are the lights mains or 12V?

Nope unfortunately not new houses.
My place is originally like 100 years old.
It was refurbished as a guess 4 years ago.
So I would expect in that time they have worked.
At worst from a timeframe standpoint the previous owners from me would have been the installers who owned it for a year prior to me.

Much goes the same in terms of situation with my friend.
The only correlation I can see is that we are both living close to Maida Vale and are both from the Southern Hemisphere - So maybe it's a conspiracy
The dimmers don't look cheap. At least from a visual standpoint they look like quality.
They are chrome/silver looking with nice turning buttons.
My and her's whole place is fitted with dimmers throughout.
No other issues like this to report.
They both just happen to be in the bedroom.
Seems pretty weird then.
I thought my issue was common as anything, given it happening to the both of us in a short time span, and the exact same style of erroneous behaviour.

Best bet is to replace the dimmers with a quality make (e.g. MK Logic Plus Intelligent), adequately rated for the load. In the absence of any specific information on the dimmer about its rating, if you're using it for mains halogens pick one rated at twice the load of the lights.

If you're using it for 12V halogens make sure of the following:

1) The transformer can be dimmed.

2) The dimmer switch can handle transformers.

3) The type of dimming is compatible between both transformer & dimmer - there are two types, leading-edge or phase delay, and trailing-edge or phase cut, and what the dimmer does must match what the transformer needs.