Monitor help needed please

[welsh rat]

Hi everyone, just wondering if anybody can help with a monitor problem I have?
I own a Missile Command tabletop, the problem is that at the top of the screen only half of the high score shows (it seems like it has been cut in half) I've tried adjusting everything that can be turned but no luck. It just seems that the upper end of the monitor does not work. Any help would be greatly appreciated. (I hate it when I dont know how to fix something.lol) Hope the picture shown what im trying to explain.

[Ken Layton]

Try the "Vertical Size" and/or "Vertical Linearity" controls. If those don't do it then your monitor needs a capacitor kit. You'll need to know the brand and model of the monitor in order to order the correct kit.