I recently switched to S video cabling between my DVD player, my receiver, and my TV. I now notice (it may have been there all along) a faint vertical line moving from right to left on my screen every 5 - 7 seconds whenever I play DVDs. A slight distortion, a slight irritant, and one I'd like to avoid if possible.

As the question may suggest, I am a home theater neophyte and have little technical understanding of such issues, so any help/education much appreciated. What's causing this (please don't say poor equipment!)? What if anything can be done about it?

Many thanks!