My 50" LG plasma TV (about 4 years old now) has recently begun showing what I can only describe as 'digital noise' at the top of the screen. It shows up as a field of blue pixels in a randomly shaped band about 1 1/2" thick across the top and sometimes only in the corners, of the viewing area. It only appears if that area of the screen is trying to display something very dark or black-ish, like a night scene. If that area is displaying any other sort of brighter color, like yellows or even whites, the blue pixels are not visible, (or at least, not obviously, nor easily, visible). This occurs even when viewing a DVD so I don't think my cable service is the culprit. It also seems to abate after the set 'warms up' for say 30 minutes.
Lastly, I'm also tempted to think that the set's quality may also be deteriorating and/or, this deterioration (if real) may be related to the blue noise. My daughter recently got a new LCD TV which absolutely blows away my set's image, which I once thought was the best quality on the planet. Then again, maybe it hasn't deteriorated and the new LCD's are just that much sharper and crisp? Has anyone else had a similar problem with LG's or any other similar plasma set? Is there some sort of 'degaussing' technique that might be done (and how?) to clear up the noise and perhaps even restore the image quality if the two in fact are related?
Thanks