Then I got black screen on a new ATI 9250 128 MB PCI! But this video card can run fine on a PC Windows.
Was it completely black from the start? I mean, did you even see the open firmware texts at boot or was it just MorphOS (logo and so on) which was black? Did the monitor give any signs of life (leds indicating it gets some kind of signal etc)?
So black I thought I had a faulty video card: no Open Firmware and no signal from 3 LCD monitors.