The last Roku with analog outputs was the Express+ 3910, which was released in Oct of 2017. If you just bought it, it was not new. There are no Roku players that will work with an old CRT TV, unless it's one of the early HDMI equipped sets. And even those usually don't support 1080p. In fact, some only support 1080i and 480p on the HDMI port, neither of which are supported by any model Roku.
It sounds like the TVs you've tried don't support the resolutions that the Roku does. For your Express+, that is 720p and 1080p on the HDMI port and 480i analog with the yellow RCA connector. Which connection are you using?
I have a hunch that a replacement will do the exact same thing. If you can check it on a TV that supports 1080p, you can see if it's working correctly, and possibly change the display to the correct analog setting. I've never connected a Roku to an analog TV, so I don't know exactly what that setting might say on the Roku menu.
With your old TV, you might simply be out of luck trying to get a streaming player connected. None of the currently available devices (Roku, Fire TV, Chromecast, Apple TV etc.) offer an analog connection any longer. I see an Express+ 3910 on Amazon for $150. For that price you can buy a new HDTV that supports 1080p that is probably close to the same size as your old CRT set. Some users have had success using an HDMI to analog converter box, and those can be found from $25 or so online. I can't offer one that is known to work.
Dan
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee, just another user.
