Interest in music videos began to wane in the late 1980s. USA Network cancelled its "Radio 1990" video program in 1986; MTV suffered a ratings slump that same year that led it to replace its original crew of video jockeys and begin creating non-music programs; and in the summer of 1987, "Friday Night Videos" was pushed back an hour to accommodate a Friday episode of the higher-rated "Late Night with David Letterman". In 1989 TBS began cutting back the amount of airtime devoted to music videos. Beginning in March, 1989, the Friday night schedule comprised one hour of "Power Play" (see below) and one three-hour block of videos, beginning at 1:00 AM ET/10:00 PM PT. TBS assigned the cut three hours to live sports events on Friday evenings and reruns of "Hogan's Heroes" and "Gomer Pyle, U.S.M.C." early Saturday mornings. That August, TBS reduced "Night Tracks" to two and a half hours on Friday, and "Chartbusters" (see below) plus two two-hour blocks on Saturday, while the remaining hours each night were assigned to "Night Flicks" (which was simply a movie, standard TBS evening fare, with the "Night Tracks" theme music and announcer introducing the commercial breaks). In the spring of 1990, it was further reduced to two 90 minute blocks. (This meant that it was possible to see the first 90-minute block again (albeit in abbreviated form just before the cut off time) on the same night.)