I was living in Harford County, Maryland, in the mid 70s, and I was inexpressibly THRILLED when Channel 48 out of Philly began running DS in syndication, I think at 11 p.m. weeknights, in late 1975 or Jan. 1976.
I was moving around a lot in those years but I believe that Ch. 48 was still running the show ten years later, in '86. I believe that shortly thereafter they stopped showing it.
Best, G.