Flashing/dead spotlights - faulty transformers??

[ajc123]

Hi. I'm new to this site but hope you can help! I have 20 ceiling spots in my flat which have always been quick to go out, but they are now all flashing or dimming or not working at all. I've tried the obvious (ie changing bulbs) with no joy and have been told it's something to do with transformers, which are up in the ceiling and not easily accessible.

What can I do to resolve this, it's getting embarassing having emergency table lamps dragged into the bathroom for guests in case it goes dark and we're sick of living in a disco! We also tried lower wattage spots (the originals are 50 and we tried 12 I think). Do we need to get an electrician in or is this a common problems with spotlights, as I know others whose are also unreliable!

Please help cos its driving me mad!

Thanks

ajc

 

[JohnD]

Are the lamps screw-in, pins or bayonet fitting? Is the socket they go into plastic or porcelain (I am thinking about them getting loose due to heat)

You mention transformers, so are they 12volt or what?


edited to add, it is dangerous to drag a table lamp into the bathroom. Have a think about changing to a nice enclosed ceiling lamp in there, preferably with a compact fluorescent inside, and say goodbye to lamp failures.

 

[Al-Glasgow]

Sounds like the fault lies in transformer as advised.

You will need to access it somehow, i guess you have recessed ceiling maybe.

take out a bulb holder and look with a torch.

Al

PS. use 230vac spotlights with proper wattage then you wouldnt have this problem.

 

[ajc123]

So if I look at the trasformers how would I know they are faulty?? And would it cost much / be easy to change them?? We have got a recessed ceiling but some fittings pull out more then others.

The lamps are pins into plastic, not sure on voltage. I know the lamp is not ideal but cannot afford to replace the ceiling unfortunately! It's more dangerous trying to shave my legs in the dark (no window!)!.

THanks, I really appreciate your help
ajc

 

[Al-Glasgow]

First of all locate any transformer unit, or remove a bulb and read voltage rating etc.

If you can get into tranformer supply cables, then you could disconnect the transformer and connect the 230vac direct to new 230vac spotlights.

If you intend to fault find the transformer then you will need to find the output details....eg 12vdc 500ma.

Hope this helps
Al

 

[ajc123]

Thanks Al, will try locating the transformers first, assume I am not looking for robots in disguise - haha! Would they be easy to replace?

 

[Steve]

Thanks Al, will try locating the transformers first, assume I am not looking for robots in disguise - haha! Would they be easy to replace?

You are looking for a smallish rectangular box with ratings such as
PRI: 230V AC 50-60Hz
SEC: 12V AC 60VA

Trannys may be overloaded - compare the VA output of the tranny to the wattage of the lamps it is powering. There's no such thing as a 12W bulb - you were looking at the voltage. LV halogens are commonly rated at 10, 20, 35, 50w. You may also have cheap trannies - i expect someone on here will point you in the direction of a good brand! Fairly easy to replace - disconnect wires from both sides, put back into new tranny - job done. Also check they are not sitting in insulation - they dont like overheating.

 

[securespark]

Erm.....

Buy a voltage tester that covers 12-230VAC

Remove each light fitting in turn from the ceiling. If you are lucky, you will be able to gently tug on the lampholder to reveal the transformer. Use the voltage tester to ascertain the presence of mains voltage at each transformer (or if there isn't one, 12V at the SELV lampholder).

If you have mains on the primary, then check to see if there is voltage on the secondary side. If not your tranny is goosed. If you have 240 in and 12 out, then check the lampholders - they often wear out due to heat damage.

Easy when you apply logic.

PLEASE USE SAFE WORKING PRACTICES

 

[macmini]

not sure if everyone else has noticed or not.

However, it would appear that the original poster said transformers, i took this to mean that there are multiple transformers throughout the installation, so it seems to me to be a wiring fault before the transformers, not a fault with them or the wiring to the lights themselves.

Could be wrong though.

 

[securespark]

I have in the last week replaced on two separate jobs 12 transformers & 6 lampholders, after which, all the lights were working again.

So in my experience it could still be trannies.

I have noticed: my previous post advised to go round all fittings and check for mains voltage.

 

[macmini]

Fair enough.

Just thought it'd be rather unlikely for all the trannies to die at once.

 

[michael-przybysz]

I'm a fresher in the world of electriks so if all fittings are flashing at the same time I would start from checking the switch or dimmer if she has one.

 

[breezer]

I am an old boy, i suggest you dont reply to posts that were posted last year