Bathroom spotlights not working - transformer?

steviep43

Hi all
For about 6 months my 4 bathroom spotlights have all been going off together at random intervals. By turning the switch off, counting to 5, then switching back on they then come back on. They'll either stay on for the rest of the time or go off again. However 3 days ago they stopped working altogether so I now have no light in my bathroom. I have:
1) replaced all the bulbs
2) replaced the switch
3) checked the connections as well as I can
None made any difference. The extractor fan which works off the same switch is unaffected and works as normal. Having checked the wiring set up in the loft, I have 1 light that comes off the transformer, and the other 3 that are connected in a line with each other also coming off the transformer separately from the 1st. As all 4 turn off at the same time, I am assuming that the transformer is at fault. It's not overheating as they turn off completely at random. Any electricians able to back me up on my theory? If so, how easy are they to replace (I'm ok-ish at electrics, having changed a few switches and sockets etc. in my time, but no expert). Given the current isolation issues I won't be able to get an electrician out for a while.
Thanks in advance.

Le_Kirk

Sounds like you have eliminated everything but the transformer.  If you have power going in and nothing coming out, it must be the transformer but, unless you can test for voltage in with a multi meter you are reduced to replacing the transformer - an expensive test if it proves not to the that.

grumbler

What sort of spotlights are they? It's worth considering replacing them with mains voltage ones. It can be about the same price as replacing the transformer, but prevents similar problems in the future.

steviep43

grumbler said:

What sort of spotlights are they? It's worth considering replacing them with mains voltage ones. It can be about the same price as replacing the transformer, but prevents similar problems in the future.

They're RU16 two pin LED bulbs. I didn't think that would be an option. Is it easy to do?

Hasbeen

steviep43 said:

grumbler said:

What sort of spotlights are they? It's worth considering replacing them with mains voltage ones. It can be about the same price as replacing the transformer, but prevents similar problems in the future.

They're RU16 two pin LED bulbs. I didn't think that would be an option. Is it easy to do?

Check the ceramic holders? They tend to burn out slightly and do not make a good contact with pins. Try and spread the pins slightly and push in move side to side and switch on

Le_Kirk

Hasbeen said:

steviep43 said:

grumbler said:

What sort of spotlights are they? It's worth considering replacing them with mains voltage ones. It can be about the same price as replacing the transformer, but prevents similar problems in the future.

They're RU16 two pin LED bulbs. I didn't think that would be an option. Is it easy to do?

Check the ceramic holders? They tend to burn out slightly and do not make a good contact with pins. Try and spread the pins slightly and push in move side to side and switch on

Would that affect all lamps?

steviep43

I meant MR16, not sure where I got RU16 from! Having looked at the transformer in the loft (pic attached) it says that it's for dimmable halogen lamps, 75-200VA. Having done some further reading, I gather this isn't suitable for LED non-dimmable as it's too powerful. Could the replacement at some point of a halogen bulb with an LED have caused this issue? I don't remember replacing a bulb so it may have been a while ago. I think I need a transformer of much less wattage. Am I correct?

Le_Kirk

You just need one that works and is suitable for the voltage, type and number of lamps to be connected to it.  The 200 VA shown on the label is a maximum.  Whilst VA is not exactly equivalent to 200 Watts, itis a good indication.

Hasbeen

Le_Kirk said:

Hasbeen said:

steviep43 said:

grumbler said:

What sort of spotlights are they? It's worth considering replacing them with mains voltage ones. It can be about the same price as replacing the transformer, but prevents similar problems in the future.

They're RU16 two pin LED bulbs. I didn't think that would be an option. Is it easy to do?

Check the ceramic holders? They tend to burn out slightly and do not make a good contact with pins. Try and spread the pins slightly and push in move side to side and switch on

Would that affect all lamps?

Yes if all fitted at same time = wear.

Hasbeen

steviep43 said:

I meant MR16, not sure where I got RU16 from! Having looked at the transformer in the loft (pic attached) it says that it's for dimmable halogen lamps, 75-200VA. Having done some further reading, I gather this isn't suitable for LED non-dimmable as it's too powerful. Could the replacement at some point of a halogen bulb with an LED have caused this issue? I don't remember replacing a bulb so it may have been a while ago. I think I need a transformer of much less wattage. Am I correct?

Had 1 of these for each undimmable MR16 light worked well for years then started to get problems with dry solder joints at output cable. Resoldered a few times rarely, if I remember correctly at output end? then changed to mains GU10 LED"s.

Turn power off, pull cover's off disconnect power in, taking clamps off and see if there is any movement at terminal block at power out. If so remove circuit board and resolder from rear.

Or get new replacement ?  https://www.screwfix.com/c/electrical-lighting/light-transformers/cat840844?cm_sp=managedredirect-_-lighting-_-transformers 

Or do as I did and change to mains.

grumbler

steviep43 said:

grumbler said:

What sort of spotlights are they? It's worth considering replacing them with mains voltage ones. It can be about the same price as replacing the transformer, but prevents similar problems in the future.

They're RU16 two pin LED bulbs. I didn't think that would be an option. Is it easy to do?

Don't know what RU 16 bulbs are, but I meant replacing the fixtures, not just the bulbs.