With my Thunder/24, there's a setting in the classic Monitors control panel (under Options...) that allows me to display at 1024x768 with a reduced refresh rate and sync on green turned off ("no SOG", to be precise). I believe it was at 60 Hz.
That should do it, I think. Monitors that don't support sync on green with some video cards can produce a washed out picture that's tinted either white or green. I've seen both on one monitor of mine with two different Radius cards and the integrated video of a Quadra 800 mobo.
As for how to get that setting to show up, you might need Dynamic Desktop as well, which doesn't work under OS 8.6. Not sure what software alternatives there are... maybe SwitchRes has some option you can use to turn off SOG?
That should do it, I think. Monitors that don't support sync on green with some video cards can produce a washed out picture that's tinted either white or green. I've seen both on one monitor of mine with two different Radius cards and the integrated video of a Quadra 800 mobo.
As for how to get that setting to show up, you might need Dynamic Desktop as well, which doesn't work under OS 8.6. Not sure what software alternatives there are... maybe SwitchRes has some option you can use to turn off SOG?