Minutes after the Prince William County School Board unanimously voted its confidence in Superintendent Richard M. Johnson and his budget proposal last night, the county teachers association announced it had voted "no confidence" in Johnson. That set the tone for the evening.

Parents, teachers, members of the black community and former students accused the board of ignoring parents' concerns, allowing administrators to intimidate teachers who attempt to complain and needlessly removing a black administrator.

Most of the 120 persons who attended last night's public hearing on the budget were protesting cost-of-living raises for teachers that Johnson said should be held to 3 percent. The average Prince William teacher makes $17,000 a year, which is less than teachers make in Fairfax and Arlington counties.

Anthony Futyma of the Prince William Education Association, said the teacher group's members plan to campaign for candidates running for the County Board of Supervisors this year who will seek to have Prince William School Board members elected rather than appointed.

At one point, Judie Cook, a parent, scolded the board, declaring that Johnson "works for you, you don't work for him. But I tell you most of the county thinks you work for him. You're supposed to listen to your constituents, not Richard Johnson."

Johnson, superintendent since 1980, and the seven board members sat unflinchingly through the hearing, then the board approved Johnson's $113.6 million budget request, which goes to the Board of Supervisors.

Futyma said the teacher organization plans to vote today on a job action in which teachers would give up all after-school duties and volunteer activities. "We're most disenchanted," he said.