In an unprecedented move, members of the Utah Symphony and the management of the orchestra have announced a renegotiation of the musicians' contract, originally not due to expire until September 1991.

Under terms of the new contract announced Thursday, the musicians have agreed to accept an increase in their minimum salary to $601 per week, effective March 1, instead of the $650 per week stipulated in the previous contract, ratified in 1988. The current minimum is $566.50. In addition, the revision includes a one-year extension of the contract through Aug. 31, 1992.The new pact comes after a resolution two months ago by the symphony board to limit the orchestra's 1990-91 budget deficit to $350,000 vs. the $750,000 originally projected and reduce the deficit to zero by 1991-92. At that time the deficit for 1989-90 was estimated at a record $1.79 million, since increased to $1.9 million.

According to board chairman Deedee Corradini, the new agreement together with administrative cuts have reduced the annual budget by nearly $500,000, for a total of $6.4 million.

"There never has been a time when the symphony musicians and board leaders worked so closely on behalf of the common good of the orchestra," she said. "We now have in place a structure through which we can continue to cooperate in meeting our annual fund-raising goals and balancing the budget in the next two years."

Of the symphony's last three contract agreements, two have been reached following strikes, the latest, in 1988, lasting nearly a month. Thursday's announcement comes after six weeks of negotiations, spurred by what both sides described as a "critical" financial situation.

"Had we waited," said musicians negotiating committee chairman Gerald Elias, "there was a danger that the entire structure of the organization could change radically." The musicians, he said, wanted it understood they were "flexible in terms of salary, but inflexible on cutting back on the size of the orchestra or the number of services."

At present the symphony presents about 200 concerts a year, of which 75 are school concerts.

Reportedly, the musicians' vote, taken Nov. 16, was 55-18 in favor of the new contract.

"It's no secret that, when in comes to salaries, we lag behind other major orchestras," commented one of those in favor of the pact, "and I think the other votes reflect frustration over that. But given the realities of the situation, we would much rather work together and try to get there eventually, rather than take the route a lot of other orchestras have taken of breaking down and quitting."

According to executive director Paul Chummers, other provisions in the new contract include a revision of the vacation schedule that will permit two more weeks of concerts in the summer, currently the orchestra's most lucrative period. In addition, musicians' representatives will now serve on both the fund-raising and budget and financing committees of the board.

Also announced Thursday was the extension of music director Joseph Silverstein's contract through the 1993-94 season. Hailing the new musicians contract as "exemplary," he said it showed "a more productive level of communication between the board and the orchestra" than he had seen anywhere else.

Silverstein was appointed the orchestra's conductor in 1983.