Ronn Teitelbaum, 61, who founded the '40s-style Johnny Rockets hamburger diner chain (with 138 restaurants in 25 states and nine countries), died of brain cancer on Monday in Los Angeles, where the first Johnny Rockets opened (on Melrose) in 1986. Before Teitelbaum came up with the idea for his malt shop, which looks like something out of the set of "The Adventures of Ozzie and Harriet," he operated a Beverly Hills men's clothing store.