Basically, yesterday i hooked my AppleVision 1710AV up to my Performa so that i could watch Bathurst in my computer room (go Holden btw ), and i noticed that the raster was only about half the width that it normally is. (height is fine) Anyway, i adjusted the settings, no such luck. Then i wacked it a few times, and it went back to normal. It did the same thing today, too. Presumably, that means that there is a loose connection or a cold solder joint or something to that effect inside.

Having never done component-level repairs on a monitor before, i'm wondering...how would i go about finding the problem?