Roku tv started making chirping sound today. It does it while unplugged, while streaming and while on home. It has been reset on the tv itself, as well as factory reset on the settings menu with it still remaining unresolved.
If your TV is under warranty then contact ONN. Roku Doesn’t make TVs. They only make the operating system. So your TV is unplugged (now power to it at all) and it makes a chirping noise? That’s kinda impossible.
Are you using any type of sound bar or external speakers? Are you 100% positive the chirping noise is coming from the TV? Did you take the batteries out of the remote? You have an answered the rest of my questions? Is the TV less than a year old? If it is it’s covered under warranty so you need to go to ONN and speak with them. Roku cannot warranty your ONN TV
Have you tried contacting Onn support yet to inquire further? I'd suggest starting there to see what options or suggestions they can provide. Each Roku TV manufacturer provides direct support for their products running the Roku OS.