I'm getting red lines in a set of parallel, horizontal lines on my several-year-old Sony Trinitron CRT TV. Any ideas what's causing it? I should mention that they've always been there, but I never did anything about it. Doesn't seem to be a function of anything (brightness, color, hue, etc.), pretty constant -- more visible in darker scenes.

They might be helical, but if so, the diagonals are much less pronounced. There's about a dozen+ across the entire screen.