I have a CGA monitor that I got from the US (it is 60Hz) and I'm trying to use it in the UK, with 50Hz mains. When I try to use it with either of the 2 CGA cards I have, the video constantly moves across the screen. Is this an issue with the mains frequency or can I adjust something inside the monitor to fix it? The monitor has a H-Phase adjustment on the back that doesn't appear to do anything, V-Hold, which I can adjust to make the picture move up or down the screen, and a V-Size which stretches the image.
Here's a photo of the monitor