Picture too big for screen

Reset your ratio settings per manufacture instructions.

Try VIEW MODE button on the remote or ZOOM button on the remote from cable box.

An adjustment in the cable box fixed the problem.

There is a button on your remote control that controls the TV's zoom level. It is usually labeled WIDE MODE or ZOOM.

First, you have to tell me how the cable box is connected to the TV, by HDMI or component. If it is connected by HDMI, the cable box settings will override the picture size settings on the TV. It may be as simple as resetting the picture size on the cable box, but I am not familiar with the type of cable boxes that Comcast uses.

I had the same problem. My cable company told me to press the # button on my remote to change it from "zoom" to "normal" and it solved the problem.