In a down-to-the-wire School Committee race, Robin A. Harris, a sixth-grade teacher at the Benjamin Banneker harter School, was poised to upset committee incumbent Alfred B. Fantini, an unofficial tally of votes showed last night.

The initial count of No. 1 votes gave incumbent Alice L. Turkel, a member of the liberal Cambridge Civic Association (CCA), 2,565 votes, the most of the eight contenders for the city's school board in yesterday's election.

Another CCA member, Susana M. Segat, received 2,581 votes. David P. Maher of the moderate Alliance for Change party followed with 2,152 votes. Voters cast 2,046 ballots for Joseph G. Grassi, another Alliance candidate; 2,026 for E. Denise Simmons of the CCA; and 1,972 for Harris, also a CCA member.

Fantini and challenger Charles L. Stead Sr., both endorsed by the Alliance, received the fewest votes, 1,740 and 953, respectively.

Challenger Harris' apparent victory would give the CCA a two-seat majority on the Six-member committee.

Under the city's proportional representation electoral system, the ballots of the candidates who garner more No. 1 votes than a certain quota are passed on to the next highest-ranked candidate on those tickets.

Analysts predicted last night that the ballots of the two top vote-getters, Turkel and Segat, will be reallotted, mostly to Simmons and Harris.

The results of this vote reassignment--which will be finalized today--are expected to secure positions on the committee for incumbent Simmons and challenger Harris, although a surprise cannot be ruled out.

"I'm feeling much better," said Harris, reacting to the news that she may have regained the seat on the committee that she lost in the 1995 election. Her seat was taken by Segat.

Harris enjoys support among current members of the committee.

Fantini, who along with the other Alliance candidates did not attend the vote tabulation at the Cambridge Senior Center last night, was unavailable for comment early this morning.

CCA President Geneva T. Malenfant offered a reason for Fantini's poor showing.

"I didn't see any sign of Fantini doing anything until maybe a week before the election," she said.

According to preliminary figures, more than 16,000 votes, several hundred fewer than in the last election, were cast in the School Committee race, according to the preliminary tally.

"There were very few issues out there," said John O'Sullivan, president of the Cambridge Teachers Association (CTA).

The board's most public accomplishment last term was the selection of a popular new school superintendent, Bobbie D'Alessandro, to succeed Mary Lou McGrath.