I had my Roku set up and it was working, today when I change the input the TV says there’s “no signal” as if there is nothing plugged in there. I unplugged and plugged the power to Roku back in and even hit the reset button on it. When I do that the Roku bouncing thing comes on the TV but once it’s done the TV displays “no signal again.”
So, you changed the tv input and it shows no signal? Change it back to whichever input it was on. If that doesnt do it, try unplugging tv power and plugging back in to have it redo the handshake that hdmi needs.