Samsung LCD 46

I have a Samsung LNS-4692D. The picture is outstanding as long as I use component cables. When I use HDMI, whether it be thru a DVD or the Directv box I get a video retention on dark scenes. They clear up when the scene changes to a well lit scene, exp-- outdoors. Samsung has replace the TV once. Has anyone had similiar problems and what is the cure? The Tv is still under warranty. Any help would be great. Thanks, Jim