I recently had two HR24-500 receivers installed and immediately noticed a degradation in picture quality on SD channels. The picture appears grainy, and is especially on any alpha-numeric characters that appear on screen. Characters appear as if they are composed of blocks, with absolutely no smooth scaling on the edges. HD picture quality is great. I found several posts from a couple of years ago describing the same issue, but nothing stating any resolution to the problem. Anyone know of a fix?? any help appreciated.