Ok, here's my own problem that developed in the last couple of days:
I have an SVGA on one computer that suddenly flipped to very poor
color. It went back and forth a few times for a day, but stayed in the
poor color state for all of yesterday. So this morning I started
characterizing the problem a bit.
Using RGB settings in any program: blue appears black, green appears
bluegreen, and red appears red. (Plus the natural combinations... such
as "yellow" appears pure white.) So blue hits no phosphor and green
hits both blue and green. This occurs in both Windows and Linux, and
when I swap monitors between computers it is a characteristic of the
monitor not the computer.
Any ideas? Does this just need degaussing or is it likely to be an
electronic problem?