In message , Paul
writes:
J. P. Gilliver (John) wrote:
In message , Paul
writes:

Many LCD monitors don't make it to 25000 hours, because
the high voltage inverters (more than one present on
the larger monitors), those fail and can no longer
give the 700V to 1000VAC the lamps need. Each lamp
(Is it always AC?)

Absolutely.

The requirements are pretty strange, in that the
AC must be "pure". You can't have any DC at all in it.
If it isn't pure AC, the tube will die a premature death.

Interesting. (Bit like LC displays, though for a very different reason.)
[]
If you take an LCD monitor (w. CCFL) apart, make *special note*
of how all the foil materials are positioned. They're
part of the circuit (capacitive coupling) and must be
put back the way you found them. There's an entire

Thanks for the tip. (The only one I ever dismantled was because the LCD
part had failed (bottom two inches of display went white), no problem
with backlight.)

book on the topic of care and feeding of CCFLs like that.
(A guy in sci.electronics wrote that book.)

Many companies have made mistakes when setting up their
illumination sources, which is why the move to LED
lighting is such a nice improvement. Any dope can do
LED lighting (and not have it die a year later). Of
course, bleed is always a problem, and the more dopey
manufacturers can't even seem to get that right. The
display is edge-lit and it helps to have hired someone
with a background in optics.

Paul
My last six months' employment were with a company that, among other
things, repaired car dashboards. Really old ones had lots of little
filament bulbs; most modern ones do indeed use lots of white LEDs.
(Which are awfully bright when seen without the display housing in
place!) Some - particularly Mercedes - did indeed have tube lights; had
to be handled with care.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

All humanity is divided into three classes: those who are immovable, those who
are movable, and those who move! - Benjamin Franklin