I have an Apple monitor I picked up a few years ago. Unfortunately, it did not do too well in shipping, so it arrived with a few broken plastic pieces, and the video looks like the photograph.
It can't be fixed through any of the four external knobs - it seems like some kind of horizontal hold problem. Any suggestions for internal adjustments or components I can check?
BTW, the computer works fine with my Monitor /// and any other composite monitor I try.
I think you should start with a thorough visual inspection of the inside. This level of physical damage on the outside suggests a similar level on the inside. Look for damage around the deflection yoke and for cracks in the board around the heavier components.