What was going on when I was born?

A lawyer who defended a Salvadoran national guardsman convicted of murdering four American churchwomen said yesterday that he had been forced to take part in a ''conspiracy'' aimed at preventing higher-ranking military officers from being implicated in the case. The lawyer, Salvador Antonio Ibarra, said that another defense lawyer had pressed him not to contradict a statement that ''the possibility of a cover-up had been thoroughly investigated'' and rejected. Mr. Ibarra said that declaration was ''an outright lie'' and added that he was specifically warned not to pursue the case on his own. After it became clear he would not cooperate fully in the plan, Mr. Ibarra said in an interview, he was abducted by Salvadoran security forces, held prisoner at National Guard headquarters and tortured. The objective, he said, was to get him off the case, either by killing him or forcing him to flee the country.

The battered old green car pulls up outside P.S. 29, an elementary school in the Cobble Hill section of Brooklyn. Out jumps a tall, handsome man in blue cotton pants and running shoes, all grace and exuberance in the morning. Jacques d'Amboise, the legendary principal dancer with the New York City Ballet who has been reborn as the Pied Piper of dance, has arrived. The children of P.S. 29 know him as Jacques - ''that man who dances,'' as Nicole Gonzalez, a kindergartener, describes him. When he bounds through the door, it is as if an electric current had passed through the corridors and classrooms: Jacques's here! Everyone from the security guard at the front door to the women serving lunch in the cafeteria starts smiling.

The seven astronauts aboard the space shuttle Challenger ended experiments today and stowed equipment in preparation for their scheduled landing here Monday at the end of what has been hailed as a highly successful seven-day mission. The Challenger is due to swoop in from the South Pacific, rake Los Angeles with a sonic boom from 90,000 feet and alight on the dry lake bed of the Mojave Desert here shortly after 9 A.M. (noon, Eastern daylight time). The landing was originally scheduled to take place at Cape Canaveral, Fla., but the hard landing of the Discovery spacecraft there last month, which damaged that shuttle's brakes, blew one of its four main tires and seriously frayed the other three, led officials of the National Aeronautics and Space Administration to switch sites as a precaution. Reason for Switching Sites With the Spacelab scientific laboratory nestled in its cargo bay, the Challenger is 12 tons heavier than the Discovery, and the almost endless dry lake beds here provide more flexibility in case of trouble.

An article in Business Day on Thursday about the Unocal Corporation misstated the personal tax impact on the company's management and directors from a possible enlargement of an offer to buy back shares. By increasing the number of shares it is offering to acquire, Unocal could not minimize the taxes they would have to pay on stock profits.

Dale Berra considered it a routine play, just a basic part of the game that he learned in high school and took with him to the big leagues. But to Billy Martin, it was a revival of Yankee tradition. Berra's aggressive slide into second base yesterday prevented a double play and kept alive the fifth inning for the Yankees. The inning ended with three runs on back-to-back homers by Rickey Henderson and Don Mattingly that helped the Yankees to a 6-2 victory over the Kansas City Royals.

In the 1950's and 60's, when the civil rights movement was challenging the old order across the South, a group of white civic leaders in Atlanta began preaching a gospel of accommodation rather than confrontation. They took to describing Atlanta as ''the city too busy to hate,'' and with the help of local blacks like the Rev. Martin Luther King Sr., they set out to dismantle the legal barriers of segregation in hotels, lunch counters, jobs, schools and government, with little of the disruption and none of the violence that occurred elsewhere in the region. ''When they were putting dogs on people and beating them up in Birmingham,'' said Mayor Andrew Young, who plans to seek a second term this fall, ''blacks and whites in Atlanta sat down together and worked out their differences around a table.'' That spirit of cooperation may have had less to with racial enlightenment that it did with an abiding pragmatism among civic leaders here who argued that racial strife was bad for business. Still, over the last two decades, this cooperation has worked some powerful truths in Atlanta.

It was the scene that many had feared. At the main crossroads of this small town, policemen with plastic antiriot shields confronted an advancing crowd of Jews, many of them wearing the badge that accompanied their parents and grandparents to their deaths: a six-pointed yellow star bearing the word Jude. The Jews came from 21 countries, but many were from France, Belgium and the Netherlands. One big blue banner hoisted in their midst read in French, ''Neither hate nor forgetfulness.''

For the fourth time in five years, the Milwaukee Bucks will spend the summer pondering what might have been were it not for the Philadelphia 76ers. The surging, confident 76ers completed a four-game sweep at the Spectrum this afternoon with a 121-112 victory before a crowd of 15,264. They have eliminated the Bucks in four playoff meetings in the last five years. But this was their only sweep in those meetings, and it served notice that the champions of 1983 were back. That season they won 11 of 12 playoff games. This was their seventh victory in eight games. They eliminated the Washington Bullets in the opening round, three games to one. They now have a week off while awaiting the winner of the Boston-Detroit series. At the earliest, the Eastern Conference final would not begin until next Sunday.

Rupert Murdoch, the Australian publisher who bought a half interest in the 20th Century-Fox Film Corporation in March, is expected to announce today that he will buy at least six television stations from Metromedia Inc. for about $1.55 billion. The deal, which would include WNEW-TV Channel 5 in New York, as well as stations in Los Angeles, Chicago, Dallas, Houston and Washington, would be the largest group sale of independent television stations. Mr. Murdoch and Metromedia's chairman, John W. Kluge, spent Saturday negotiating the deal in Mr. Kluge's apartment in the Waldorf Towers. The same day, the Hearst Corporation announced that it had agreed in principle to buy Metromedia's seventh television station, in Boston, for $450 million.

Tens of thousands of people marched down Fifth Avenue and gathered near the United Nations yesterday in a demonstration of support for Soviet Jewry that participants said was colored by anguish over President Reagan's visit to a military cemetery in Bitburg, West Germany. ''Why not admit it, today we are wounded,'' said Elie Wiesel, addressing the rally in Dag Hammarskjold Plaza at 47th Street and First Avenue. Mr. Wiesel is chairman of the United States Holocaust Memorial Council. Placards and Chants ''Is there a connection between Bitburg and this rally?'' he asked. ''Yes, there is. What was attempted at Bitburg - a denial of the past, a disregard of Jewish agony - the same but on a larger scale has been attempted in Russia.''

For decades, the tough methods used against criminals by a Prohibition-era detective, Johnny Broderick, were widely sanctioned in New York City's police force. Roaming the streets of Manhattan, Detective Broderick clubbed suspected gangsters and hoodlums with a lead pipe wrapped in a newspaper. Police officials in the late 1960's tried to end that type of brutality. In response to public complaints about pervasive police misconduct, training programs were established that emphasized sensitivity and civil rights in dealing with suspects and the public in general. But a recent string of incidents, including purported assaults with an electric stun gun, has raised questions about overall police behavior and the effectiveness of Police Department programs to prevent misconduct. Last year, 6,698 complaints were filed against city police officers for purported mistreatment and excessive force - about 600 more than in 1983.

An article on the Style page last Monday about a convention of the New York State chapter of the National Organization for Women carried an incorrect listing, based on information from the United States Comptroller General's Office, of states that are acting upon the results of pay-equity studies. The states are Iowa, South Dakota, Minnesota and New Mexico.