Moving vertical grey bar appearing sometimes

[prouton]

I've got a small problem with the display on my PVR-1 (specs below). Not consistently, but roughly 2-5 times in a 30 second period, I see a vertical band of grey (a darkening of the picture) that moves from right to left on the screen. The picture itself is rock steady. The video signal is being fed into a Phillips CRT television via the s-video port.

It takes it about a second and a half for the bar to traverse the screen, and it can either be following immediately (as soon one disappears of the left side, another one appears on the right) or not at all. I say 2-5 times because it's very random about how many times it appears in a row. The time between groups also varies. I haven't noticed it on the GB-PVR menu screens, just during recording playback and live TV.

From these symptoms I would rule out regular noise sources, such as fans or A/C power, but am at a loss as to what is causing it.

Any thoughts?

[herbs]

Please post a picture of the screen when it happens, use something like imageshack to host the image.