In article ,
Frank Erskine writes:
What's the normal failure mode for low energy lamps? I have (had!) an
Osram Dulux 20W/827 lamp just above me and all of a sudden it failed -
no flickering, no dimming - it just went out!
It's temporarily replaced with a 40W candle bulb which was lying about
downstairs until tomorrow.

Some months back, I wrote a whole section on this in the wikipedia
entry for fluorscent lamps...
http://en.wikipedia.org/wiki/Fluores..._end _of_life

If the tube ends are blackened, then it's the first choice "Emission
mix runs out", otherwise it's probably the second choice "Failure of
integral ballast electronics".

--
Andrew Gabriel