One recent morning, 99-year-old Don Weidenbach tinkered with a balky humidifier on a workbench in the basement of his senior condo building in Edina. He's volunteered to repair busted lamps and small appliances since he and his wife of 68 years, Charleen, moved there in 2010.

"My dad was no good at fixing things, so I started early β€” tightening loose doorknobs and fixing toilets as a kid," he said during a break for lunch.

Weidenbach blossomed as a digital computer pioneer after World War II and forged a 30-year career as an electrical engineer in the early years of Minnesota's computer tech era. Through a dizzying swirl of mergers and spinoffs, companies such as Remington Rand, Sperry, Univac and Control Data emerged.

Throw in Honeywell and IBM's massive Rochester facility and, by 1960, Minnesota was an early Silicon Valley β€” and Weidenbach was right in the thick of it.

"Back then, the word 'computer' wasn't even part of the vocabulary," Weidenbach said. "We were concerned there wouldn't be a market and they wouldn't last because they were too large, used thousands of vacuum tubes and cost more than a million dollars a unit."

All that changed 75 years ago this month, when an electronics company called Engineering Research Associates (ERA) opened its doors in St. Paul's Midway district near the old Montgomery Ward store. Computer pioneers like Weidenbach moved into a large industrial plant at 1902 W. Minnehaha Av., where wartime gliders had been built. Backed with military contracts, ERA started as a secretive company to continue the U.S. Navy's code-breaking advances that ramped up after the Japanese attack on Pearl Harbor caught the nation off guard in 1941.

While with ERA, Weidenbach developed magnetic drums the size of car tires that stored information β€” the grandparents of today's hard drives. A commercial computer he designed enabled a catalog company to punch in phone orders and track inventory; 70 years later, we do the same with phones in our pockets.

Weidenbach grew up in Scotland, S.D., and earned an electrical engineering degree at South Dakota State College in 1943. After joining the Army, he was trained as a radio communications expert and served in the Philippines during World War II.

In November 1946, he took a bus from Scotland to Kasson, Minn., meeting up with Army buddy and fellow engineer Bob Erickson to go job hunting in the Twin Cities. First stop was Honeywell, where they were told it would be months before a job opened. They visited a switchboard manufacturer, which "sounded boring," Weidenbach said.

Then a stop at the state employment office tipped them to engineering openings at ERA in St. Paul. "They wouldn't tell us much about their classified work," Weidenbach said. "But the mystery intrigued us and we accepted their job offers."

His initial monthly salary of $215 added up to $2,580 annually, less than $35,000 a year in today's dollars. But his connections led him to buy stock in Control Data.

"We were the technicians, building prototypes and running tests," he said, as ERA shifted from specialized military computers to more general purpose ones.

Early ups and downs left Weidenbach worrying if there would be paychecks on Fridays. But by 1952, ERA employed more than 700 tech workers with a backlog of orders totaling $8 million.

The Speed Tally computer, which Weidenbach designed in 1950 with no government money, became his "pride and joy." He quarterbacked a team of technicians and engineers that enabled a mail-order company in Chicago to store its 13,000-item catalog in a drum memory. Keyboard operators could find out how much stock was available, subtracting items that were sold and adding new merchandise when it arrived.

"It sounds ridiculously simple in today's world, but 60 years ago it was on the cutting edge!" Weidenbach wrote in 2012 for the VIP Club, an association of retirees from Minnesota computer tech companies.

By the time Weidenbach retired in 1976 at age 55, ERA had become Univac and his accomplishments ranged from magnetic drum memory breakthroughs to innovations for airline reservations and air traffic control. He also helped develop Athena missile-launch computers for the military.

He and Charleen moved to Bloomington in 1960 and raised five children, none of whom followed their dad into computers. But all three daughters married engineers.

"Don is a member of the greatest generation," said Lowell Benson, a retired Univac engineer and leader of the VIP retirees group that this month is marking the 75th anniversary of the first time ERA pushed the power button on Minnesota's computer age. "He can be proud of being an IT pioneer."

But first, there was that leaky humidifier to fix.

"It reminds me of those horrible vacuum tubes that never lasted back in the late 1940s," Weidenbach said.

Curt Brown's tales about Minnesota's history appear each Sunday. Readers can send him ideas and suggestions at His latest book looks at 1918 Minnesota, when flu, war and fires converged: