This can be a complicated issue.

There is more to the CRT than just the heater. When there is cathode
current, the ware is higher. There is a minimum cathold current when
there is no brightness on the screen. The tube has to be biased
slightly on all the time when working, even though it is in black.
When there is some luminocity on the screen, there is a greater amount
of cathode wear in the electron-gun.

Having a black screen saver will infact save some amount of catholde
wear. If you have a small image on the screen that is moving around,
this would introduce a bit more cathold current, but it would not be
the same amount as having a full screen of white.

The best solution is if the screen is not being used for about a 2 to
3 hour period, turn it off, or have the Windows power savings utility
turn it off. Cycling the monitor power on and off, can introduce a
greater stress on the support components, and the tube, rather than
simply leaving it on. This gets in to duty cycle statistics on the
wear of the electronics, and tube. This can get very complicated in
many cases.

The standard CRT should last about 30,000 hours. At this time factor,
the brightness output should be about 50% of the nominal. This figure
is with the brightness set to normal, and the contrast at about 50 to
70% of its maximum rage. If the monitor is used at about 10 hours per
day, it should last about 8 years.

In reality these monitors will last about 5 to 6 years. There are many
support components that can go wrong before the tube does. Cycling
the power off and on will also cause the monitor to fail quicker.
After about 6 years of normal use, many of the capacitors start to go
bad in monitors and TV sets. Then there are many other types of
components that can fail. Since most monitors, unless they are very
expensive and high end models, they are designed to not be serviced.
In the low to medium end monitors, many of the manufactures don't sell
the parts for out of warranty servicing.

Enjoy the monitor. The way things are going obsolete these days, in a
few years, your monitor will be useless, and may have to be changed
anyways.


Jerry Greenberg
http://www.zoom-one.com

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Halfgaar wrote in message ...
Hi list,

I've read in a DPMS screensaver help file that blankscreen screensavers are
not such a good idea, because when the CRT filament is still energized when
there's no picture, actually causes the life of the CRT to shorten. Why is
this?

TIA

Halfgaar