A juror, who is the key figure in the recent request by millionaire Dominic F. Antonelli Jr. and D.C. mayoral aide Joseph P. Yeldell for a new trial, testified yesterday that she did not know when she served on the jury that her father had ever been fired by Antonelli's parking firm.

"Did you in any way learn directly or indirectly that your father had worked for PMI?" the juror, Diane P. Jones, 27, was asked yesterday by Judge Gerhard A. Gesell during a U.S. District Court hearing. PMI (Parking Management Inc.) is Antonelli's parking company.

"No," the juror replied. She testified that she had not recalled her father's previous PMI employment when she was chosen as a juror and she added, "My father has never told us that he has been fired from a job."

The hearing, during which Jones and her father both reasserted statements they had previously made in interviews with The Washington Post, was called because of Antonelli's and Yeldell's contention that they had been denied their right to a fair trial. They have charged that one juror, Jones, was biased against Antonelli because of her father's firing from a PMI job in 1967.

Yesterday's four-hour court hearing was marked by several novel legal turnabouts, including a repudiation by the juror's father, John H. Jones, of major parts of a sworn statement he signed that was previously filed in court. John Jones had already disavowed key parts of his affidavit in a Washington Post interview.

As a result of Jones' testimony, Edward Bennett Williams, Antonelli's chief defense lawyer, took the witness stand yesterday to vouch for the authenticity of Jones' original affidavit. Williams testified that he had read aloud "every line" of the affidavit "slowly and carefully" to Jones before Jones had signed it.

"He (Jones) said all things in it were true," Williams testified.

At another point in the hearing, the juror's mother, Helen, burst from the witness stand in tears, crying. "Please take me out of here, please take me out of here, what else do you all want our of my daughter and me&" She had apparently been provoked by persistent qusetioning by Yaldell's lawyer. John A. Shorter Jr. who was later rebuked by Judge Gesell for asking what he termed "highly irrelevant" questions.

Judge Gessell said he plans to rule Monday on whether Antonelli, a real estate investor and influential businessman, and Yeldell, who is on unpaid leave from his job as a top aide to Mayor Walter E. Washington, are entitled to a new trial. The two men were convicted of bribery and conspiracy charges after a three-week trial last month. They are scheduled to be sentenced Nov. 30.

Antonelli and Yaldell, both of whom watched intently from the defense table during yesterday's hearing, were convicted of conspiring corruptly to arrange a highly profitable city government lease of a Northeast Washington building from a partnership controlled by Antonelli. In return for Yaldell's assistance in securing the lease, Antonelli was found by the jury to have given Yaldell a secret $33,000 personal loan after helping him obtain short-term loans from a bank in which Antonelli is a stockholder and director.

There appeared to be two fundamental issues in yesterday's arguments over Antonelli's and Yaldell's new-trial plea. One is whether the juror, Diana Jones, was biased against Antonelli. She and her parents all testified yesterday that she was not. The defense lawyers had previously asserted in requesting a new trial that Jones, the juror, had "recognized consciously or subconsciously, an opportunity to settle an old family scare" by serving on the jury that convicted Antonelli.

A second issue appeared to be Diane Jones' failure to disclose during the jury selection procedures at the start of the trial that her father was currently an employer of a Diplomat Parking Corp. garage. Williams Antonelli's chief defense lawyer, has argued that Jones' failure to reveal her father's employment in response to one of Judge Gesell's questions to prospective jurors had denied the defense an opportunity to raise further questions that might have led to Jones' exclusion from the fury.

Jones, the juror, told Judge Gesell yesterday that she had failed to disclose her father's occupation because she does not have "a close relationship" with him, "did not think of my father" when she heard the question, and may have misunderstood the question or failed to hear part of it. At a later point, she made it clear that, rather than seeking to serve on the jury, she would have preferred to be excused from it because jurors were to be sequestered at a local motel for three weeks.

"I didn't want to be locked up for three weeks," she said.

Near the end of yesterday's hearing, Judge Gesell told prosecution and defense lawyers that the credibility of the juror's father, John Jones, had become a significant issue. Although Jones' affidavit was central to the defense request for a new trial, Jones has since disavowed parts of it and Jones himself was revealed in court yesterday to have been convicted of gambling offenses and to have joked at home about getting a $30,000 to $40,000 payoff for signing the disputed affidavit. There was no allegation that any payoff actually was made.