Season 1 ABC , 1976 Season 2 ABC , 1976 - 1977 Season 3 ABC , 1977 - 1978 Season 4 ABC , 1978 - 1979 Season 5 ABC , 1979 - 1980 Season 6 ABC , 1980 - 1981 Season 7 ABC , 1981 - 1982 Season 8 ABC , 1982 - 1983