Super Nintendo Background glitch

[Kujo]

I have had my Super Nintendo for about five years now, and the entire time it has shown a very odd graphical error. It causes the backgrounds in games to move at a slower than normal pace. And in over the top games such as Final Fantasy and Zelda, it completely ruins the textures of the background and makes a shaking motion. Other parts become crooked, and the whole game looks like a mess. Only character sprites and Mode 7 seem to be unaffected by this. Games like Super Mario World and Mega Man X have completely misplaced sprites(Mario World the power up icon in the box at the top of the screen and a assortment of enemies in Mega Man.) I know it is not the cartridges because I have used them in other Snes to a better result.
Since the games are still playable, I have been able to "live with it" for all this time. However, an hour of playing Final Fantasy III(or VI) gave me a serious migraine. So I am fed up with it and am in look of a solution. My problem with is that I cannot seem to find somebody who has experienced the same problem as I am anywhere. On top of that, I have no idea how to word it. So I am completely lost here.

This is a video of the issue http://www.youtube.com/watch?v=1nuHbnKQIck&feature=plcp


Thank you.

[sparf]

I'll defer to the experts here, but the basics are have you cleaned the cartridge slot? I have seen a lot of weirdness like that on a few systems because of dirty connections that are intermittent.

Barring a problem with that, the PC repair technician in me wants to call this a problem on the microchip level. But that's just a guess and isn't worth much. Someone else here will probably know far better and know it for sure.