Eliot Curtis was in the middle of an electronics repair job when he found himself experiencing very strange sensations at his home workshop on a recent evening.

It turned out that Curtis, Broadcast Operations Manager for Bay Area news channel KPIX, had accidentally ingested LSD from a vintage Buchla synthesizer that he’d volunteered to repair for the California State University East Bay—confirming a long-running urban legend that some of these trippy-sounding instruments were dipped in the drug in the 1960s.

Curtis told KPIX that as he began to clean the synthesizer, he discovered a crusty substance inside of it.

“There was like a residue … a crust or a crystalline residue on it,” he told KPIX’s Juliette Goodrich.

About 45 minutes after cleaning the residue with his bare hands, Curtis began to experience the tingling feeling associated with the onset of an LSD trip. Three chemical tests later confirmed that the substance stuck to the vintage synthesizer was indeed acid—which explained why Curtis felt different for the following nine hours.

The Buchla synthesizer has a long history in Bay Area counterculture. Don Buchla, of Berkeley, developed the instrument in 1963, when he was friends with the Grateful Dead’s engineer Owsley Stanley. Ken Kesey of the ’60s counterculture group the Merry Pranksters took several Buchlas aboard their famous “Furthur” school bus—a fixture of acid-fueled, freewheeling hippie culture of the time.

Read more about the case of Curtis and the curious synthesizer on KPIX.