I have a similar problem, where one or two scan lines from the bottom of the picture appear at the top of the picture...
In my case, it's not the TV. It's the Motorola 62xx HDDVR box.
That HDDVR is flaky at best. The solution is to unplug the box, then plug it back in. The picture returns to normal... until next time.
This may not be your exact problem, but what the heck, give it a try.
I started using the "Just Scan" picture mode because I thought it would be the most true to the intended aspect ratio. It usually looks good but I have found that in some cases when a HD channel is showing content that is apparently not in the 16:9 aspect ration (not sure if that means the content itself is not HD) I get a horizontal line across the very top edge. It is hard to describe but reminds me of the overlap you would see on old TVs when you had to play with the scroll to keep the picture from rolling. In other words, kind of like the bottom edge of the image has wrapped around to the top. I'm not saying that's the case, or even that it's possible, just trying to describe it. If I change the mode to 16:9 it goes away. I don't think this happens on all channels even when they are not in the 16:9 mode, so I'm not sure what's going on. Maybe it is something about the source. Also, I tried moving the image when in Just Scan mode, but that didn't seem to do anything. I don't mind switching it to 16:9 if I'm going to be watching it for awhile, but it is then 16:9 for everything else. Maybe I'm too concerned about the 16:9 vs Just Scan and should leave it at 16:9, but then what's the point of Just Scan? Anyone have any ideas or suggestions? Thanks.

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