Samsung DLP picture is zoomed in

[jweaver]

My Samsung DLP television is several years old. It had worked great until recently. Now, the picure is "zoomed in" except on HD channels. I tried cycling between normal, wide, zoom and pan picture modes but the picture is still zoomed in in normal and wide and worse in the zoom and pan modes. Significant portions of the top, bottom and sides of the picture are not in view. We have compared the pictures on HD channels against non-HD channels for the same program - the HD looks normal, the non-HD is zoomed in with significant parts of the picture edges lost. I would have thought this problem is caused by the mirrors being out of adjustment, but the television has not been jarred/dropped and the HD picture is normal. I have searched through the menus and find nothing that fixes or changes the problem. Has anyone seen this problem before? Does anyone have any advice on what to trouble shoot or even whether it is worthwhile to call in a technician?