Outer Limits 4x4 Board

my 240 blitz light force spotties, i noticed the other night my spotties arent as bright as when i frist bought them. so i took the cover off to have a good look inside and noticed by bulbs have a black (burnt look) on the inside top of the bulb. i know there on there way out but what is cuasing this?

i pretty much use my spotties everyday and i have had from for nearly a year now.

thanks in advanced

oil from fingers that touched them when they were installed. whenever i change lamps i give them a wipe down with a tissue moistened with metho to remove residue off the glass, or install them wearing gloves.

Hard to imagine finger oil getting into the INSIDE of the glass envelope.

What its likely to be is deposited tungsten from the filamaent that was deposited on the glass after continued short cycling - especially if its got a metail sheen to it.

Finger oil usually shows up as a brownish stain when burnt off

This is common with downlights operated with dimmers the temperature doesn't get hot enough for the halogen cycle to capture the vaporised tungsten and it ends up deposited on the envelope inner.

With down lights, if you operate them at full intensity for awhile they get to the point where the halogen re scavenges the tungsten and they pretty well clear up ( this is recomended by the lamp manufacturers.... )

Perhpas a sustained on period might help, but with the price of petrol perhaps just new bulbs.....

if it was from oil of fingers it wasnt me then, it would have to be done by light force as this was the first time for me to take the cover off.

from what you said mighty mouse, i can sorta understand what you were sayin. sorry im not the best with electric's. but it sounds right with what your sayin.

im just gona keep them till they blow and buy rally 4000's with an HID kit.

thanks