After triggering a pop of electricity by touching a screwdriver to metal in a disassembled cathode ray tube monitor, Chi-Tien Lui issued a warning to visitors gathered in his cluttered workshop on a recent Friday morning. “That voltage doesn’t kill you,” he said. “But it really hurts you.”

For the record, Mr. Lui, 75, was unharmed. He carried on with his lesson about how to remove a circuit board, then opened it up to hands-on participation. The students in his shop, CTL Electronics, in TriBeCa, were from an art conservation program at New York University. They were studying electronic art, including works by the pioneering Korean-born artist Nam June Paik, and their professor had arranged a half-day session with Mr. Lui, a technician with whom Mr. Paik had a long association.

“It feels very special and lucky that we’re able to meet him and to be here while he still has his studio and all of the equipment he has stockpiled,” Lia Kramer, 29, said. She pointed out a 1940s-era Motorola television set that looked like those used in Mr. Paik’s sculptures.

Christine Haynes, 25, was similarly impressed. “To see what people would have been working with….” She trailed off, clearly awed by the antiquated equipment crammed into the workshop.

When Mr. Lui started CTL Electronics in 1968, he was at the vanguard of an artistic revolution. He began the business intending to install and repair video systems for businesses, universities and private clients. But around then, Sony released the Portapak, which for the first time put portable video-camera technology into the hands of consumers — and artists. Mr. Lui shifted to embrace the nascent medium.

During Mr. Lui’s nearly half-century career, his clients have included Andy Warhol, Bruce Nauman and Mr. Paik, whom he met in 1969 when the artist brought in a video camera for repair.

Today, Mr. Lui’s workshop on Murray Street is stuffed to the pressed-tin ceiling with thousands of vintage televisions, video cameras, VCRs and other equipment. With the advent of digital devices and smartphones that capture and distribute video with the tap of a finger, Mr. Lui has been fortunate to segue into conservation, providing the components and technical know-how to maintain analog-based artwork.

One such work is Mr. Paik’s 1963 piece “Zen for TV,” included in the Museum of Modern Art exhibition “From the Collection: 1960–1969,” on view through March 12. He is also sharing his knowledge with conservators and students in order to keep such works alive in the future.

“Very few people know how to work with those materials now,” Raphaele Shirley said of the obsolete technology. An artist, she was an assistant to Mr. Paik, who died in 2006, and now works with Mr. Lui on conservation projects. “He has the ability to understand the perspective of museums and artists,” she added. “That’s a really rare quality for a technician.”

That quality has made Mr. Lui a sought-after teacher for those working in time-based media conservation, a relatively new discipline that focuses on technology-dependent artwork.

Mr. Lui has worked with numerous institutions, including MoMA, the Whitney Museum of American Art and the Solomon R. Guggenheim Museum. In September, he taught at the Smithsonian American Art Museum, in Washington, at the invitation of the museum’s media conservator, Dan Finn, who was eager to study old-fashioned TV maintenance and repair.

A highlight for Mr. Finn was learning how to replicate Mr. Paik’s “Zen for TV.” The piece is deceptively simple: a TV turned on its side that displays no more than a vertical slice of silvery light in the center of the screen.

“You’d almost worry that that sort of unveiling of a trick behind an artwork is sort of akin to revealing the secret behind a magic trick, and that maybe it loses something,” Mr. Finn said. He found the opposite to be true. “It almost made the work more impressive.”

Born in Chongqing, China, in 1941, Mr. Lui moved with his family as a teenager to Taiwan, where he trained as an electrician. He also took classes in television repair, which was challenging, since he had never actually seen a working TV. “The only thing on the screen was snow,” he said. “So we were repairing TVs, pretending there was a broadcast.”

He saw his first broadcast in 1960, when the ship he worked on as an electrician for the Taiwanese merchant marine arrived in Los Angeles. At 19, while docked in Baltimore, Mr. Lui jumped ship and headed to New York City, where he got a TV-repair job in the Bronx and later enrolled in technical school. “I didn’t even know English,” he said. “But I knew diagrams.”

In 1965, he married an American woman, a painting teacher at Bellevue hospital, whom he met while recovering from tuberculosis. Eventually, he found work designing and servicing video systems. As his reputation grew, Mr. Lui decided to start CTL Electronics, working at first out of the couple’s Reade Street loft, then opening a shop on West Broadway, where he sold video cameras, equipment and supplies. Artists were frequent customers.

According to Mr. Lui’s daughter, Jennifer Lui, 49, they would ask: “Can you help me do this installation? Can you put this monitor in a shoe?” She added, “I think deep down that is the part he enjoyed the most.”

Though Mr. Lui has floated the idea, Ms. Lui said she had no plans to take over the shop, which opened on Murray Street in 1995. In fact, she sees no easy solution to preserving her father’s legacy. “Because she can’t do what he does,” she said, referring to Ms. Shirley, Mr. Lui’s associate. “I can’t do what he does. I’ve been telling all the museums, use him or lose him, because he is a resource.”

In the United States, only a small number of schools offer training in time-based media conservation. At N.Y.U., Hannelore Roemich, a professor of conservation science, and Christine Frohnert, the art conversation professor who took her students to Mr. Lui’s shop, are developing a graduate specialization, part of the 2018 curriculum, that will be the first of its kind in the nation.

Compared with traditional art conservation, which deals with, say, restoring Impressionist masterworks or Renaissance sculpture, Mr. Lui’s work is more demanding. “It becomes so much more difficult when it has a plug,” is how Professor Frohnert put it. It is crucial, she said, for conservators to forge relationships with experts in related fields, like Mr. Lui. “Our students need to meet him,” Professor Roemich added. “They should know about him.”

Professor Frohnert’s association with Mr. Lui goes back to at least 2010, when she and a fellow German conservator named Reinhard Bek began a collaboration with Mr. Lui and Richard Bloes, senior video technician at the Whitney, to restore a couple of Mr. Paik’s works as well as Earl Reiback’s “Thrust.” All of these cathode-ray-tube-based artworks reappeared last year in the Whitney’s inaugural exhibition in its new downtown home.

Mr. Bloes met Mr. Lui around 1978, when he went to CTL Electronics for videotape. “I probably would have forgotten it if he hadn’t been just so grumpy at first,” Mr. Bloes said. Years later, Mr. Lui is his go-to technician.

Mr. Lui has pondered the future. “Starting a school might be interesting,” he said. “Maybe a museum.” But Mr. Bloes suggested that even if Mr. Lui passed on his arcane knowledge, he knew of no one who can truly assume his mantle. “That’s the million-dollar question right there,” Mr. Bloes said. “The thought of somebody else taking over might be hard for him.”