Weird light issue

[Lee Nowell]

Hi All,

A friend was around yesterday and she was describing an issue she is having with one of her lights. In the bathroom she has a number of spot lights (believed to by 240v) and when switch on, all lights come on as normal. When she turns them off, one of the lights flashes on and off continually. It would appear as though this is fully on then fully off (i.e. not dim).

This has only recently started to happen and no work has been done on the house to suddenly cause it. I did wonder if for some reason an emergency light was fitted (i.e. as in offices where they come on in the event of power loss) but apparently they are all the same and no little led lights on them to indicate these.

I can not think of anything that could cause this behaviour. Anyone have any ideas?

thanks

Lee.

[John]

Lee Nowell [e-mail]> wrote in news: [e-mail]:

So - you imply a dimmer switch is in the circuit? /Is it a touch or remote type?

[Lee Nowell]

Sorry didn't mean to imply dimmer. Was trying to say that the on state when flashing seems to imply mains live and not some sort of residual current from somewhere (where I would have assumed the bulb would be dim).

[Chris Hogg]

Is it a filament bulb, fluorescent, halogen, LED or what. The explanation might be dependent on the bulb type.

[Andy Burns]

Has one of the incandescent or CFLs have been replaced with an LED? if the cables to the light run parallel to other cables they could have enough capacitance that lets the PSU inside the LED slowly "suck up" enough power to give a brief flash, then rinse and repeat.

Another possibility, is if the lamps turn out to be 12V halogens with a transformer, rather than 240V, a transformer might have gone faulty.

[Lee Nowell]

Will check re: the LED.... I too was originally thinking dud transformer but then was thinking that might be the case if the light flashed on a few times due to the capacitance on the transformer but given it apparently goes on "for ever" I ruled that out. Have got her to send me some photos too which may unpick things

[The Natural Philosopher]

I can think of dozens

[The Natural Philosopher]

Not if its an LED.

Or a fluorecscent

[The Natural Philosopher]

If it has, take it out and patent it.

A transformer that produces voltage on the incendiary with the primary underpowered would be worth billions and a Nobel prize.

[Chris Hogg]

^^^^^^^^^^

^^^ <chuckle>

[tabbypurr]

Possibles:

1. Leakage R in bulb has gone o/c, now it's powering from capacitive cable coupling
2. dodgy switch or wiring

NT

[Brian Gaff]

Well first swap the lamp between sockets. If it moves then its the lamp. I'm assuming these are LEDs? Brian

[Brian Gaff]

Dodgy spell check, must be related to mine. Yes I agree something like that has to be rather more than a faulty transformer.

Swapping bulbs will prove the point and reveal the culprit as I said. Brian

[Brian Gaff]

I can recall many years ago when Leds were in their infancy the almost on problem afflicted on, and the fix, in the end was a 1 megohm resistor across the socket. Weird things LEDs. Brian