H20 1080i with 1080p sharp tv problem

[laggs]

My tv is set to view mode dot by dot and when I tune to a 1080i channel I notice that there is a blank horizontal space on the top part of the screen (about 20 pixels wide). Does anyone else have this problem? Is my image shifted down? This phenomenon happens on both of my sharp 1080p tvs.
Thanks,
Laggs

[texasbrit]

My tv is set to view mode dot by dot and when I tune to a 1080i channel I notice that there is a blank horizontal space on the top part of the screen (about 20 pixels wide). Does anyone else have this problem? Is my image shifted down? This phenomenon happens on both of my sharp 1080p tvs.
Thanks,
Laggs

It's very common; in fact many TVs that have this mode discuss it in the user manual. To start with, it usually means (as you suspect) that your TV picture is not centred correctly. Adjusting it may mean getting into the service menu. But in general, using this mode can be a problem since it is basically setting the "overscan" of the TV to zero, and even with a correctly centred picture this will often result in what looks like interference at the top or bottom of the picture (in the interscan, where the closed caption information is transmitted). Many people use an overscan of about 4-5% which pretty well guarantees no problem.