>The phrase is: "TK-421, why aren't you at your post?"

You're absolutely right. I have that number burned in my head as well, because when I was a kid I had a pop-up Star Wars book with a sound effects tape to go along with it, and that phrase was one of the sound effects.

Ever seen the movie Boogie Nights? Remember the black porn star guy that was also a hi-fi salesman? He pushed a factory stereo enhancement for one of his products that was the "TK421 modification". Sub-conscious random model # on the part of the authors? Or subtle reference?