Had your monitor been repaired before ?
Don't you have any other video source, besides the Amiga 2000, to confirm that the monitor is really weird ?
If the YOKE was invert connected to the monitor main board you can see a picture as you described. But it's really odd, as the connector that plugs in the monitor mainboard do not connects reversely.
The only way to do that, is to solder the wires in reverse places, on the YOKE itself. But it could your problem.
If you don't know what a YOKE is, please consider asking a technician some help, because this circuit (horizontal deflection circuit) on monitors and TV sets deals with high voltage.
If i can help in any other way, you can private mail me.
Regards.
