On newer ships you have to disconnect the TV from the ship network, remove power and reapply power to free the TV from it's locked state.  If you have your own remote then at this point input button should work but not always.   On some ships once the TV has been cycled as noted above the menu button on the ship remote brings up a factory TV menu and under the "Support" menu you can change inputs using the ship remote.    These pictures were taken in a balcony cabin on the am