I have an HR24-100. During playback of recorded programs, I get intermittent flickering, about once every 10 to 15 seconds, where a white band flashes on the screen then disappears. This happens only during playback, and not when watching shows in real time. I've had this problem in the past with other types of DirecTV boxes as well as this HR24-100, and it's getting very tiresome. Does anyone have any suggestions?