I'm having the exact same problem with my Roku TV... Going from over the air antenna channels to streaming, the streaming channel blacks out after a few seconds. Have restarted the Roku TV twice. Reset picture settings.
This only started after I installed the Roku Backgrounds app. It never happened before that. I uninstalled the Roku Backgrounds app and restarted the Roku TV... Twice. But it keeps happening. I've been using this TV for months without this problem... It only began after installing Backgrounds.
Heres what i have been able to figure out so far: it only happens on live channels. I also have an antenna and those channels have no issue. I use subtitles. When the channels go black the subtitles still follow along with the audio without disappearing (so its not a whole screen thing, its a channel thing). If i use the system power off/restart it fixes it for a couple days and then will start it again. No system updates needed. Has not happened when using any apps so far its just the live tv streaming channels. Channel doesn't matter i will try several of them and they have all blacked out but audio and subtitles are fine. My moms tv has started doing the same thing. Both are Onn tvs. Different sizes and models and years
