[geeks] CRT life with brightness at 0?

[wa2egp at att.net]

>I've been thinking of using one my modified Mac SE/30 machines as a 24/7 
>home firewall, and I want to preserve the CRT as much as possible.  Of 
>course the computer pre-dates energy saver, so it is always on, but it has 
>a manual brightness control knob that can be turned all the way down. 
>Will that preserve the lifespan of the tube?  Will the phosphor life or 
>anything else be affected with the brightness set to 0?

I don't think the phosphors would be a problem since they "burn" when
being lit up by the electron beam.   If the brightness is down, there should
be no problem.  They only thing I would worry about is the filament being
on the whole time.  I really don't know the actual lifetime of a CRT filament.
I'd rather have a burned phosphor than a burned out filament! :->

Bob