>>6051185
That would also be consistent with the flickering horizontal bands I see, which indicate the connection coming undone multiple times within a single refresh cycle due to vibrations.
I've just done a quick test in photoshop. I took a colorbar image, turned it to grayscale, and then subtracted the grayscale from the original image. The result looks exactly like what I see on my monitor.
If the problem is a bad joint (easily a plausible suspect on this 27 year old display), does this failure mode tell me anything about where I will find the problem?