While the diner closed down years ago, it is still frequently used for filming. Check out the video collection of movies filmed at Quality Cafe here.
From "The Diner" segment. in episode 1x06 "Candlestick/The Diner/From the Agency/The Magic Rose Garden/The Jeep".
Eddie and Lila having pie & coffee.
From episode 1x06 "Outside Man".
David & Michael meet for lunch.