Even when leaving work to be treated for his irregular heartbeat — “They stop my heart and start it up again, like rebooting your cable box” — he is back at the shop immediately afterward.

“I’ve left work for a hernia operation, I’ve had stents put in, and I was always here in the morning,” he said. “Don’t ever say work killed me. It kept me alive.”

What is dying is the art of TV repair, with modern flat-screen sets being difficult to fix and often disposable, Mr. Jennings said. He has fallen back on servicing custom sets in upscale apartments, and he takes on nearly any related job, from installing stripper poles in apartments to delivering sets to a local mobster’s stable of mistresses around town, he said.

“There used to be TV repairs all around here, but I’m the only one left — I put them all out of business,” he said. “I’m the longest-running shop in I don’t know how many square miles, if you’re talking same guy, same shop, same location.”

Mr. Jennings said he had customers in just about every building in the area, including the ritzy ones on and around Sutton Place.

“Bette Davis used to walk in here and call me Kiddo,” he said. “Greta Garbo would come in wearing a hat and sunglasses. She’d buy wire to fix her own lamps herself. She was thrifty.”

Mr. Jennings lives in a Forest Hills cooperative, of which he is the board president. He eats breakfast at 6 every morning at Tal Bagels near his shop with the same varied group of opinionated men, including real estate moguls and building supers.