Scooby-Doo
The first episode of "Scooby-Doo, Where Are You!" "What a Night for a Knight" debuted on the CBS network Saturday, September 13, 1969. The original voice cast featured veteran voice actor Don Messick as Scooby-Doo, radio DJ Casey Kasem (later host of radio's syndicated "American Top 40") as Shaggy, actor Frank Welker (later a veteran voice actor in his own right) as Fred, actress Nicole Jaffe as Velma, and musician Indira Stefanianna Christopherson as Daphne. Scooby's speech patterns closely resembled an earlier cartoon dog, Astro from "The Jetsons" (1962–63), also voiced by Messick. Seventeen episodes of "Scooby-Doo Where are You!" were produced in 1969–70. The series theme song was written by David Mook and Ben Raleigh, and performed by Larry Marks.
The Scooby-Doo Show
In 1977, ABC had a programming block called "Scooby's All-Star Laff-A-Lympics". The "Scooby-Doo" segment of this two-hour block included 8 new episodes of "Scooby-Doo" (two of which featured Scooby-Dum and one of which, "The Chiller Diller Movie Thriller", guest-starred Scooby-Doo and Scooby-Dum's distant female cousin, Scooby-Dee), plus reruns from the 1976–1977 season. The name of the block was changed to "Scooby's All-Stars" for the 1978–1979 season, when the program was shortened to an hour and a half, after the cancellation of "Dynomutt". 16 half-hours of "Scooby-Doo" (featuring just the original five characters) were produced this season, and began airing earlier in the morning before the "Scooby's All-Stars" block as a third season of "Scooby-Doo, Where Are You!" in September. "Scooby's All-Stars" instead aired reruns of the 1976 and 1977 episodes for the first nine weeks of the 1978–79 season. By November, the early-morning airing of "Scooby-Doo, Where Are You!" had been cancelled, and the new 1978 episodes began airing during the "Scooby-Doo" segment of "Scooby's All-Stars".