The Los Angeles Times' Randall Roberts states that by 1974, "TONTO had become a circuitous beast that included machines made by Moog, ARP, Oberheim, Roland and Yamaha; drum controllers, sequencers and, later, MIDI converters; and thick gauge wire procured from surplus supplies made for the Apollo mission and Boeing 747 manufacturing. Those familiar with Brian De Palma’s cult classic film Phantom of the Paradise have seen TONTO in action. It provides the setting for a wild scene in which protagonist Winslow Leach, donning a silver owl’s mask, performs a surreally ridiculous song on the contraption."

Roberts mentions that "Cecil was said to be furious at TONTO’s unauthorized appearance in the film." Indeed, Cecil talked about this a bit in a 2017 feature article for Music Works, written by Jesse Locke:

The pair’s invention and ambition led to an intense four-year collaboration with Stevie Wonder. The legendary artist wrote nearly 150 songs before the tracks were selected and released on his groundbreaking albums Music of My Mind, Talking Book, Innervisions, and Fulfillingness’ First Finale. During this time, TONTO was expanded to include two Moogs, two ARP 2600s, four Oberheim SEMs, modules from EMS, Roland, and Yamaha, drum controllers, sequencers, and MIDI converters, all fused together with Boeing 747 airplane wire. Jim Storyk constructed the woodwork at Electric Ladyland, studied geodesic domes with Buckminster Fuller, and then designed TONTO’s singular cabinets. Its primitive prototypes were replaced by synths rolled out on a tea trolley or a gurney, and its six-foot curves were ergonomically tailored to match Cecil and Margouleff’s heights. In a 1984 Keyboard magazine article (later adapted for the 2011 anthology Synth Gods), writer John Diliberto points to the influence of their electronic Afrofuturism. “This collaboration changed the perspectives of black pop music as much as The Beatles’ Sgt. Pepper altered the concept of white rock.”

While Wonder’s TONTO era resulted in Grammy awards, lucrative tours, and massive sales for Motown Records, Cecil claims he “never made a penny from the royalties.” Cecil bought out Margouleff in 1975 and forged a new partnership with the poet, musician, and activist Gil Scott-Heron. At the height of another fruitful period, TONTO appeared on the cover of Scott-Heron’s album 1980, which featured synth-powered songs about nuclear protests and the hardships of illegal Mexican immigrants.

TONTO went on to help shape hit releases from Minnie Riperton, the Isley Brothers, the Doobie Brothers, and countless other artists. It famously lived briefly in the studio of Devo’s Mark Mothersbaugh in the mid 1990s, and was immortalized in a parody in The Simpsons. Its best-known visual appearance, in Brian DePalma’s cult film Phantom of the Paradise, allegedly occurred against Cecil’s will.

“TONTO was at the Record Plant in Los Angeles when we were working there with Stevie,” he recounts. “During that two-year period, the studio rented the room to the film and told them they could use TONTO as a prop. No one said a word to us. When I walked into the studio and saw they were filming it, I blew a gasket!

“We eventually negotiated that they could use the footage if they paid us for the visual rights,” he continues. “The other part of the deal was that whenever TONTO appeared on screen the music was supposed to be played by the real instrument. Of course it ended up being Paul Williams’ piano instead. I’ve seen the movie a few times and it always [used to make] my blood boil. [But] I learned to let it go long ago.”