The other day I was using my laptop to play a movie via S-Video cable on my TV. I had a 3.5mm to RCA cord for sound as well.
Eventually, I needed to plug in my laptop or it would die. As soon as it was plugged in, a horrible buzzing noise came through the TV. The noise is comparable to when you touch your guitar cable while it's plugged in, for you musicians.
I tried a little error trapping, by first unplugging the s-video, and then the audio, and then both. The noise persisted for the first two options, but ceased with the third - just the movie playing on my laptop with the laptop speakers.
Any suggestions? I've never encountered this before.
Thanks!