Solving playback issues

[lsp432]

Brand new smart Roku TV, not an HDMI stick. Input from Comcast Xfinity cable box is postage-stamped (pillarboxed and letterboxed simultaneously) on every channel. Input was normal on old dumb TV. Cable box does not expose picture output/aspect ratio settings. Comcast support has nothing to contribute.

Adjusting "Picture Settings" in the Roku settings menu has no effect on picture. Every setting remains postage-stamped, including "Zoom" and "Stretch".

All search results I'm seeing deal with a picture stuck zoomed IN, not out.

Has anybody else ever experienced this? Does anyone have any thoughts?

Thank you kindly.

[AvsGunnar]

@lsp432 

Have you tried changing the "Aspect Ratio" using the Comcast cable box remote (not the Roku remote).

Select the input for the cable box and then look though the cable box menu/setup options for various video configurations you can try.

https://www.xfinity.com/support/articles/tv-aspect-troubleshooting?linkId=92114079

[lsp432]

Hello, and thanks for your response.

Unfortunately, this particular cable box doesn't seem to expose any relevant settings. It's a Xfinity-branded DC60Ux with a dead-simple remote. Basically, it's too old to have "menu" or "settings" buttons on the remote, but it's too new to have them on the box itself, which is how I used to access the aspect ratio menu circa 2010.

Comcast support informed me that they've expunged the documentation for anything but the latest equipment, so they're sending me a new box.

That said, since this existing box is only having the problem on the new Roku TV, and the picture settings menu on the TV isn't doing anything at all, it appears at first glance more like a TV-side issue. This building has two different TVs hooked up to the same model of box right now and not experiencing this problem.

Regardless of how this thread plays out, I'll update in a week or two when the new box comes in.

[lsp432]

 

Apologies for double-posting. This is the remote I'm talking about that's attached to my cable box, which doesn't have a menu button. I'm sure trying to figure out how the settings menu might work is more in the realm of "Comcast support" than "Roku support".