A Roku TV with a battery built into it will still draw some power from the wall, but most of its power will be drawn from the battery. You will have to start by unplugging the TV from the wall to check your power cord. Next, you will need to ensure that the power strip or extension cord is on, then plug your TV into the power strip.  If your TV turns on now, you know there was a problem with your outlet. If it still does not turn on after this step, then unplug it and plug it into a different outlet. If it still does not turn on after this step, then there may be an issue with your Roku TV's power supply.