TonyS Posted July 18, 2011 Share Posted July 18, 2011 Hi Chaps, Got a puzzler. I've a bathroom mirror. The mirror has eight lights that sit behind the mirror. The mirror has eight squares that aren't mirrored but are frosted, 4 in a line down each side. The two middle lights on the LHS blew and I replaced the bulbs (little things the size of your finger nail with two metal pins - you know the thing). Three weeks on and the same two bulbs blew. Duly replaced them and guess what, the same two bulbs have blown again! I'm guessing that there is something wrong with the contacts or something and I want to fix it before I blow any more bulbs. Any ideas anyone? T Quote Link to comment Share on other sites More sharing options...
kc Posted July 18, 2011 Share Posted July 18, 2011 Perhaps they are the ones getting hottest. Could there be heat sinks or cooling holes that are different on these two? Quote Link to comment Share on other sites More sharing options...
TonyS Posted July 18, 2011 Author Share Posted July 18, 2011 Good point kc - will check. Quote Link to comment Share on other sites More sharing options...
Foamie Dave Posted July 18, 2011 Share Posted July 18, 2011 Its all down to witchcraft .Another reason could be grease / sweat from your fingers on the replacement bulbs causing them to overheat. Try handling them with a clean cloth and see if it happends again .Failing that I'm with KC.....but witchcraft is still favourite Edited By Foamie Dave on 18/07/2011 19:27:15 Quote Link to comment Share on other sites More sharing options...
Doug Ireland Posted July 18, 2011 Share Posted July 18, 2011 Yep, Dave has hit the nail on the head, greasy fingers will kill those lamps quicker than that! Quote Link to comment Share on other sites More sharing options...
Simon Williams 2 Posted July 18, 2011 Share Posted July 18, 2011 Yes the grease left on halogen bulbs in particular will limit the bulbs life. Its funny most Halo lamps for security lights come with little peice of foam which you handle them by, but not these little ones. It may also be that the pins of the lamp are not making a good connection in the little socket holes of the holder, this is a recurring problem with my living room light which has similar lamps in it, and it gets worse over time. Try, if you feel comfortable doing so, giving the lamp a tweek whilst on and see if it lights up. If so you might find that your lamps are not actually blowing. Quote Link to comment Share on other sites More sharing options...
TonyS Posted July 18, 2011 Author Share Posted July 18, 2011 Right ho! No greasy fingers and give the bulbs a tweak. Check for heat build up. Conduct a witch-hunt..... Quote Link to comment Share on other sites More sharing options...
Wingman Posted July 18, 2011 Share Posted July 18, 2011 Huh! at my age a bathroom mirror is a very hurtful thing and a lit one would just be taking the p Quote Link to comment Share on other sites More sharing options...
Simon Williams 2 Posted July 18, 2011 Share Posted July 18, 2011 Posted by Wingman on 18/07/2011 21:58:50: Huh! at my age a bathroom mirror is a very hurtful thing and a lit one would just be taking the p Isnt that what your supposed to do in the bathroom? Quote Link to comment Share on other sites More sharing options...
Rob Posted July 18, 2011 Share Posted July 18, 2011 Grow a beard !!! Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted July 19, 2011 Share Posted July 19, 2011 May be a more logical possibility. If the lights are connected in parallel, then............. The transformer will feed each row of four probably into one end of the row. If the connections to the rest of the row are poor, or the wiring to the rest of the row is of doubful capacity, the light nearest the feed will have a higher voltage across it than the rest, making its life shorter. If the lights are connected in series (ie 48V transformer and 4 12V lamps) then this will not apply. Quote Link to comment Share on other sites More sharing options...
Codename-John Posted July 19, 2011 Share Posted July 19, 2011 steve if they were connected in series then if 1 blew the rest wouldnt light as it opens the circuit, and unless the connections are really poor the volt drop across the cables in a small area as a mirror would be negligable, the most probable is the finger prints Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted July 19, 2011 Share Posted July 19, 2011 Posted by neil whilding on 19/07/2011 07:13:17:steve if they were connected in series then if 1 blew the rest wouldnt light as it opens the circuit, and unless the connections are really poor the volt drop across the cables in a small area as a mirror would be negligable, the most probable is the finger prints Yes, correct, but I didn't notice in the original post whether the others stayed on or not. In the past I have found that if fingerprints are bad enough to cause a problem, they cause the glass to crack, which of course will cause the lamp to blow. Haven't seen them causing the filament to blow without the glass cracking. The voltage drop will depend on the connections and the wire size, if the wire is too small, there could be quite a big drop. Quote Link to comment Share on other sites More sharing options...
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