Occasionally, my screen fades color. Changes to purple hues and fades to grey. Color usually comes back after about 15-20 seconds, but sometimes I've got to change channels and back. This is really frustrating, especially if I'm recording something. It tiles sometimes, too. Not near as bad as Charters "digital cable" did, but frustrating nonetheless. Does anyone else have this problem, or know what causes it? Thank for your help.