When viewing HD channels in full aspect ratio, I often see a blue line on the left side of my screen. I can get it to disappear if I turn of my Comcast box and turn it back on. On some channels, full aspect doesn't work and it looks like 4:3. I have a Panasonic TH-50PX60U and am using a Comcast Motorola box with component cables. What is causing this and is there a way I can lock my aspect ratio and not have to change it to the desired setting each time.
First make sure you are using component or HDMI outputs. Now we want to set the MOT settop box to full scale and let the TV do the crunching. Large screen TV's tend to have better circuitry given their price. Turn on the Mot STB. Change to digital channel (any). Turn off the box and press menu (within 1 second). Menu should appear. Set mode to 16:9 and resolution fo 1080i. Since your TV only supports 1366 x 768 on screen (above average) it will drop the resolution to 720p (1280 x 720, progressive scan). This should allow your TV to scale properly. If this doesn't work, go back into the Mot menu and set to 16:9 mode with 720p hard-coded. Ignore other areas of screen as they only apply to low-res outputs.
Good answer Joe but I think John is expecting to get a 16:9 presentation that is not letterboxed or does not have sidebars as well on his HD channels when they are broadcasting SD programming. I may be mistaken but that is how I understood his wishes. Your soulution although correct will not accomplish this.