An article in yesterday's Business section, based on information supplied by Tandem Computers Inc., said the planned shutdown of the firm's manufacturing operations in Reston would be the first in the company's history. The company discontinued production at its Bensonville, Ill., plant last year.

Tandem Computers Inc. of Cupertino, Calif., yesterday said that it will stop manufacturing breakdown-resistant computer systems in Reston.

The announcement came as Tandem released its latest earnings report, which showed an unexpectedly large drop of 73.9 percent -- from 23 cents a share during the second quarter of 1984 to 6 cents a share in the latest quarter on revenue of $144.1 million.

The steep earnings decline makes Tandem the latest corporate victim of the industrywide slump afflicting computer companies from International Business Machines Corp. to Wang Laboratories Inc. to Apple Computer Co.

The shutdown will affect at least 55 manufacturing workers in the Reston site who build Tandem's Non-Stop brand of "fault-tolerant" computer systems. Fault-tolerant computers are favored by banks, newspapers and other companies heavily reliant on computer processing because they are specially designed to minimize breakdowns and the loss of valuable data.

The shutdown will be the first in Tandem's 11-year history, but spokeswoman Pat Becker stressed that only manufacturing operations will be eliminated at the company's East Coast division headquarters in Reston.

The phase-out in part "reflects our manufacturing productivity enhancement, and it also reflects the overall slowdown in the industry," Becker said.

According to the company, the Reston site, which began operations in 1982, is the smallest of Tandem's four manufacturing facilities. The two largest plants are in the San Francisco Bay area, and a third is in Germany.

Becker said that efforts would be made to relocate the 55 manufacturing employes rather than releasing them.

Tandem said it also is considering consolidating its Falls Church service and marketing offices, which employ 79 people, with the Reston facility, which employs 158 people, but Becker insisted that no layoffs are planned.

"The people from Falls Church have different functions than the people in Reston, and they would utilize the space that was used by the manufacturing operation," she said.