Super Friends - Season 4 Episode 3 Space Knights of Camelon
Overview: While protecting a prehistoric planet from a meteor, Superman ends up hit by the meteor's nuclear core, crash lands on the medieval planet of Camelon, and loses his memory. A bunch of rebels led by Logan take him in as their black knight in a plan to overthrow King Arthur 7. It is up to the Super Friends to help Superman remember who he is and defeat the rebels.