Hi, @hawkcl
Thanks for posting, and welcome to the Roku Community.
We understand the issue you're having with your Roku TV that keeps shutting off, and we're here to help you. If your TV keeps shutting off unexpectedly, there might be an issue with the TV's power source. For this matter, we recommend plugging the Roku TV directly to a wall outlet or try another socket to see if this helps.
If the issue persists, it might be best to reach out to Onn's support directly since they provide direct support with the TVs they manufacture. You can reach them at Onn Support
We hope you find this informaiton useful.
Best wishes,
Kash
Takashi O.
Roku Community Moderator