CHESTNUT HILL--The seven candidates for the Democratic U.S. Senate nomination found little to disagree about yesterday a two-hour debate marked by a lack of confrontation and conflict.

The seven contenders struggled to differentiate themselves on the issues of accepting money from political action committees and experience in government, but all denounced the Reagan Administration and called for reduced defense spending, increased social spending, and an end to U.S. military involvement in Central America.

One of the biggest audience responses of the night came when moderator James Randall of Toastmasters International announced each candidates' astrological sign, pointing out perhaps the greatest differences between the men.

The debate at Pine Manor College was one of a flurry the candidates have been holding recently in the wide-open race for the Senate seat being vacated by Paul E. Tsongas.

David M. Bartley, former Speaker of the Massachusetts House and Secretary of Administration and Finance under former Gov. Edward J. King in 1979, said that his experience in "two of the toughest positions" in the state qualified his for the Senate seat.

"Politics is the business of making government work and I've spent a lifetime doing just that," said Bartley, who is considered one of the more conservative in the field.

Lt Gov. John F. Kerry cited his position as a "fighter--as a veteran, as a district attorney, and as Lieutenant Governor, I've always been willing to take risks and in the Senate I want to take more," Kerry, a former Vietnam hero turned anti-war activist, has led the pack in recent polls, but only by a slight margin that many attribute to the recognition he receives in a statewide post.

Rep Edward J Markey (D-Mass.) again stressed the theme he has been using to try to turn the tables on the others, saying that "we as candidates agree on all the important issues so the important thing to think about is what sort of leader you want."

Markey, who has bathed in the national spotlight as the House leader of the nuclear freeze movement, said that he wants to go to the Senate because "that's where the next arms treaty with the Soviets will be ratified, that's where James Watt was confirmed. I want to shake the Senate out of polite discourse and into creative action."

Rep. James M. Shannon (D-Lawrence) answering a question from The Boston Globe columnist Robert L. Turner that seemed to he a direct challenge to Shannon's reputation as an "insider" who doesn't arouse the publicity someone like Markey does, said he would bring "tough policy making to the Senate."

"I think defeating Reagan is God's work," said Shannon "but there's a chance he'll be re-elected President. If he is, you're going to need people in the Senato who aren't satisfied to just sit there and point the finger of blame. They'll have to work nine-of-five to change the policies of this country."

This was the first debate since the already-infamous WBZ-TV interviews last week in which some of the candidates could not answer questions such as "Who is Israel's prime minister?" and "Whom does the U.S. support in Nicaragua and El Salvador?" Turner asked Bartley, who was embarrassed when he could not answer any of the four questions on last Monday's broadcast, what he thought of the questions' "fairness."

"I suppose it was a fair test," responded Bartley. "Voters expect a certain amount of knowledge on these issues. But we are not candidates on Family Feud."

In the test William H. Hebert missed two questions. Markey incorrectly named the prime minister of Israel and the other candidates correctly answered all the questions.

The biggest difference among the candidates again emerged on the issue of a constitutional amendment to ban abortion. Secretary of State Michael J. Connolly was the only candidate who said he would vote for such an amendment.

The audience of about 200 was roused to its only round of applause in the calm debate when Connolly challenged Bartley about money he received from political action committees (PACs) while serving as Speaker of the House. Bartley has said his campaign will not accept PAC money this year.

"I was Speaker and that's his job--to accept money from special interests so the members don't have to," joked Bartley, reminding the audience the Connolly served in the legislature at the time. "As long as you understand you got the money."

Former Hampden County Registrar of Deeds John Pierce Lynch, considered a long shot for the nomination, offered the most iconoclastic positions, calling for a summit meeting of world leaders in Boston, a four-day work week, and for the lobbying organization Common Cause to oversee all campaign contributions of more than $250