I've noticed a small area in one corner of my monitor, that has some minor "rainbowing". My plan was to use a degaussing coil on it, however as I was swapping some games I noticed that it is tied to the control panel and not the screen frame. In fact, closing the control panel causes some interference with some game carts as well... the effect is noticeable on the screen as closing it while powered on has a direct effect on the rainbowing. However, I can not find any part that is actually magnetized (tested using a compass). Anyone ever encounter this, and if so any tips on diagnostics and fixing it?