In the late 70s, there was a boom in stations specializing in disco music. Hundreds of stations adopted disco formats--only to drop them in a few years. What format were most disco stations before the boom, and what formats did they switch to after the bust? Were they mostly FM, or were there many AM stations? And did stations play dance songs all day long, or did they daypart with other types of music?
Detroit had two all-disco FM stations in 1979 - 93.1 WDRQ and 102.7 WLBS. WDRQ flipped from Top 40 in late January 1979 and, after several months of poor ratings, went back to Top 40 by the start of 1980. They later went back to dance music as an Urban station in the spring of 1982 and spent three years in that format before flipping to "Lite FM" WLTI in 1985 with Transtar's Format 41. In the summer of 1996, WDRQ was resurrected with a Rhythmic AC format (also in response to a successful format change at WKTU) which played lots of disco, later evolving into CHR by 1999.
An interesting aside... WDRQ's PD told Billboard that the station had to drop "Funkytown" after initially adding it during the spring of 1980 because the station was deluged by angry calls from listeners who thought they'd gone back to disco. They did eventually re-add the song once it became too big a hit to ignore.
WLBS was Inner City Broadcasting's attempt to clone New York's WBLS for a Detroit audience. Inner City bought the former WBRB-FM in suburban Mount Clemens and flipped it in 1978. WLBS evolved into Urban once disco died, but with WJLB and WGPR already doing the format on FM and WDRQ entering the fray in '82, LBS' success was limited and they flipped in '83 into what they called "Dance Oriented Rock," heavy on new wave. That was followed by a brief attempt at CHR in 1984 (programmed by WBLS' Sergio Dean) before Inner City finally sold the station to veteran programmer Paul Christy, who switched it to Oldies as WKSG "Kiss FM" in late '84.
Also in the late '70s, a third Detroit FM station, Greater Media's AC WMJC (Magic 95), had an evening disco block. And an AM soul station, 1440 WCHB, promoted itself as "Detroit's ORIGINAL disco station."
Down I-75 in Toledo, Booth Broadcasting, owners of WJLB, tried disco on 99.9 WKLR (which had been the market's first Soul/R&B station) in '79. 92.5 WMHE also did disco that year after losing an AOR battle with 104.7 WIOT. WKLR went country in 1981, later becoming WKKO "K100," and have never looked back. WMHE flipped to AC after the disco died, later evolving into CHR and becoming WVKS (92.5 Kiss FM) in 1990.