I have a Viewsonic PT813 21" CRT monitor, a very
high-end professional model
that I was told used to cost $1800 new (1997), has both DE15 and BNC inputs
and supports both PeeCee video and sync on green. Unfortunately it is
malfunctioning - the picture is smudged to the point of being totally
unreadable. It seems like some component in its circuitry went bad -
I don't think it's the CRT - so it's probably fixable.
A word of warning to anyone who gets this... I had an Apple Mac+ that had
a smeared display -- shaddows to the right of objects on the screen. Now,
the Mac+ video circuit is pretty simple, but none-the-less I spent quite
a time going through it, unable to find the fault.
The reason I couldn't find a fault in the video amplifier was that there
wasn't one. It was the CRT. Low emission, I think.
Most of the time, a smeared picture _is_ a fault in the video amplifier,
though. But it may not be.
-tony