Despite the gruelling pressures of serving on the Montgomery County school board, where controversies over school closings, standardized testing and minority achievement prompt hours of heated discussion, 10 people applied this week for three positions on the seven-member board.

Board President Daryl Shaw, 68, a retired Montgomery County principal, announced at the last board meeting he would not seek reelection.

"Forty-two years in the school system is enough," said Shaw.

But board members Marian Greenblatt, 38, and Blair Ewing, 47, are both vying to keep their seats. Their terms are set to expire Dec. 1.

Eight other candidates, including PTA leaders, teachers and active educational conservatives, will compete with them in the May 13 primary. After the primary, six candidates will compete for the three non-partisan, at-large seats.

Former board president Greenbelt is the veteran of the board's conservative majority. In the last election, Greenblatt's husband served as campaign manager for the back-to-basics board members Carol Wallace, Joseph Barse and Eleanor Zappone, who vote with Greenblatt on most educational issues.

If Ewing holds onto his board seat, he and Elizabeth Spencer, whose term expires next year, would be the remaining members of the present liberal minority headed by Shaw.

The present four-three split between the conservative majority and liberal minority does not prevail on every decision but has been the outstanding characteristic of the past year's board. The difference in philosophies is also the source of most of the friction and public bickering that has become one of the board's trademarks.

Most of the candidates, though, refuse to declare themselves as liberal or conservative and instead insist they are concerned with maintaining the quality of education during the coming years of declining enrollments and accompanying fiscal austerity.

In addition to incumbents Greenblatt and Ewing, the candidates are Marilyn Praisner, a 38-year-old CIA analyst active in civic affairs in her Calverton neighborhood; George Aument, 54, a Wheaton social studies teacher; Sandra King-Shaw, 43, a Rockville resident and two-term president of the county council of PTAs; Jorge Ribas, a 38-year-old medical technician in Silver Spring who is active in county civic groups and Hispanic affairs; Michael F. Goodman, 43, civil service worker from Wheaton and past chairman of the Montgomery Citizens for Education; Edward H. Gerstenfield, 43-year-old Rockville lawyer active in anti-drug paraphernalia legislation, and Suzanne Peyser, 39, an English teacher from Bethesda. Candidate David Roffe could not be reached.