Dimmable lights bulb are OK but they don't work!

[idefix]

Quite a few of the dimmable spotlights in my house have stopped working. I have tried changing the bulbs however they are OK (they work if I put them in a different place).

Each bulb is connected to a single transformer but there are no fuses there.
Any idea what could be going wrong?

 

[PrenticeBoyofDerry]

trannies have gone!
need to replace the ones that are not working, in fact it may not be too long before the rest go.

 

[securespark]

Or has the dimmer failed?

As PBD says, the trannies may have failed. Or the SELV lampholder or the connection between the two.

Often this is because the whole lot is swathed in loft insulation: if this is the case, you need to make it safe.