I purchased a Roku TV and tried plugging in my external Roku because it had a remote with a headphone jack. I tried pairing that remote with the tv, but it didn’t work. So I unplugged the external Roku and placed it with the original TV. That tv used the external roku’s remote to turn on the original tv. Now I can’t turn on that tv. What do I do??
Go into settings> remote & devices> remote> remote in use> program tv> follow prompts.
Having the remote with headphone jack control the roku tv's volume and power is not the way to get the headphone jack to work on the roku tv. You have to unplug the second roku completely, if the headphone remote were to work with the roku tv it won't work with older roku anymore. Not until you pair back. That's the next step to get the headphone remote to work with roku tv, you have to pair to the roku tv, not by programming tv, like it was a roku, as it is. Only certain models of roku tv work with headphone jack remotes.