What really happened when Gorbachev fired his colleague. THE YELTSIN AFFAIR

Five weeks after Moscow Communist Party chief Boris Yeltsin exploded in anger at a party Central Committee meeting, the Yeltsin affair continues to reverberate in Soviet society. ``We spend a lot of time trying to piece together what Yeltsin said at the plenum,'' a Soviet academic commented this week. ``Then when we've done so, we ask ourselves - why was this man fired?''

Interviews with four well-placed sources, carried out separately over the last three weeks, provide a composite version of the speech. The sources include two people who were present at the Oct. 21 plenum: Alexander Baranov, editor of the newspaper Socialist Industry, and a candidate member of the Central Committee who requested anonymity. The other two sources were a senior Soviet official and an East European source, both of whom have in the past proved reliable.

The accounts concur on the following points:

Mr. Yeltsin's speech was emotional and probably spur of the moment. Mr. Baranov says it was an ``explosion'' that lasted ``about three minutes.'' The Central Committee member described the speech as ``disjointed.''

Yeltsin described the reform policies - both in Moscow and nationwide - as being at a ``dead end.''

He attacked the Central Committee Secretariat. Baranov says he complained that the Secretariat was ``dumping on'' him.

He almost certainly criticized Yegor Ligachev, the second-ranked Soviet leader, and possibly threw in criticism of Viktor Chebrikov, the chief of the KGB (the Soviet secret police). The Soviet official and the East European source are both definite about the attack on Mr. Ligachev. Baranov sidestepped a question about Ligachev, but noted in his reply that Ligachev ``does lead the Secretariat.'' The Central Committee member refused comment.

Yeltsin did not criticize either Soviet leader Mikhail Gorbachev or his family. Baranov denies there was any reference to a ``personality cult'' surrounding Mr. Gorbachev. ``He did not pronouce a single word about Gorbachev or his family,'' the Central Committee official volunteered. The other sources concur.

There is, however, a second version of the speech circulating in Moscow - a version considerably more damaging to Gorbachev. In it, Yeltsin attacked an alleged personality cult that was growing up around Gorbachev, and complained that Raisa Gorbachev, the Soviet leader's wife, was too much in the public eye. Some reform supporters theorize that this version was spread deliberately to discredit Gorbachev. It has already served to crystallize criticism of Mrs. Gorbachev's prominence. Western visitors say a number of their Soviet counterparts devoted time last week to criticizing Raisa Gorbachev.

Even now it is difficult to know for certain what Yeltsin said. The main item on the agenda of the Oct. 21 meeting was the draft of Mr. Gorbachev's Nov. 2 address, at a meeting to commemorate the 70th anniversary of the Bolshevik Revolution. Some senior officials will not discount the possibility that the outburst was provoked in some way by disappointment at the draft. (Two intellectuals interviewed this week expressed disappointment with the Nov. 2 speech.)

Despite official assurances that reform is on track, intellectuals - in this case a senior administrator, an academic, an artist, and a journalist - express concern that reform has bogged down.

``There is a serious danger that the affair will be interpreted as a signal at all levels of the party and governmental hierarchy,'' adds the academic, who frequently represents his country overseas. ``The signal is that you do not speak out against your bosses.''

This message, the academic commented, could be ``fatal'' for reform: It could play into the hands of the regional party leaders, whose attitudes toward reform are thought to range from hesitation to downright opposition.

The academic's comments are typical of those of a number of intellectuals interviewed this week. The concern among intellectuals, who are by tradition highly sensitive to political changes, has been matched by the reaction of ordinary Muscovites. Yeltsin's removal Nov. 11 as party chief was followed by several small but unusual demonstrations of sympathy, including an attempt by young people to organize a petition in Yeltsin's favor and reports of unrest in at least one factory.

The source of the concern seems to be the leadership's refusal to publish the text of Yeltsin's Oct. 21 speech. This has led to speculation that the leadership is hiding something - either an embarrassing attack on Gorbachev or an attack on the more conservative Ligachev.

``If the [Yeltsin] speech was full of stupidities,'' says a nuclear engineer from the Soviet Far East, ``people would immediately have supported the decision.'' Instead, the engineer complains, he and other col-leagues on the periphery were ``told almost nothing about the affair.'' When told that Yeltsin had allegedly complained that perestroika (restructuring) was moving slowly, the engineer asked, ``Well, he's right, isn't he?''

Soviet officials say the October plenary meeting of the Central Committee was a confidential session similar to a Western political caucus. But they have undermined their case by publishing the text of the Moscow city party plenum on Nov. 11 which dismissed Yeltsin.

Is the affair a setback for reform? Gorbachev stresses that nothing has changed. Some reformers argue that Gorbachev had no choice but to fire Yeltsin. He was ``a bad tactician,'' one intellectual commented this week, and had thus become a liability to reform.

Other reform supporters draw gloomier conclusions from an analysis of the list of speakers at the Moscow plenum that dismissed Yeltsin.

The first three speakers to follow Gorbachev at the meeting, for example, had all felt the lash of Yeltsin's tongue in the past. The first speaker was a representative of the Ministry of Internal Affairs. On March 12 this year, the Moscow party committee expressed ``serious concern'' about a decline in police efficiency and discipline. The second speaker represented the Foreign Ministry, whose Moscow-based academy was roundly criticized by Yeltsin in July 1986. (Seventy percent of the academy's students were children of ranking officials, Yeltsin said at the time, adding that nepotism was widespread.) The third speaker had also been publicly criticized by Yeltsin, as had a number of subsequent speakers.

``It looks as if the bureaucrats are already reinforcing [their position],'' commented a middle-class Russian.