Jurors in the bribery and conspiracy trial of former D.C. Superior Court judge Robert H. Campbell said yesterday they acquitted him of charges that he accepted more than $7,000 in payoffs because they had no faith in the testimony of the government's key witness and no tangible evidence that the former judge had received any money.

Three jurors said in interviews they decided to convict Campbell of illegally accepting a gift from a local construction firm because there was a credit card receipt that showed that the company had paid for a rental truck to move the judge's household belongings in 1975.

The jurors said that they could not accept the testimony of Robert Payne Jenkins, a convicted perjurer who testified he made cash payoffs to the former judge.

"I'd say he wasn't too credible a witness," juror Robert French said.

"I was kind of concerned if [Jenkins] was telling the truth about anything because he was changing his story all the time," juror Bessie Thorp said.

Thorp, like the other jurors, knew that Jenkins faced further criminal prosecution if he did not testify truthfully as a government witness at the Campbell trial. But Thorp also seemed to agree with defense arguments that Jenkins, in order to protect himself, was willing to say whatever the government wanted him to.

"He didn't want to get back in the soup and he was just saying anything to please the court," Thorp said.

French said, "I just feel the prosecution probably put up as good a case as they could with what they had. . . They just didn't have the clinchers" to convince the jury that Campbell had accepted any bribes.

Another juror, who asked not to be identified, said that most of the panel felt that Campbell should not have allowed employes of the firm, Excavation Construction Inc., to move his household furnishings from one home to another. But, the juror said, there was "a long hangup" among the jurors in deciding whether the jury could convict Campbell of a crime in connection with the move.

In an interview, that juror recalled testimony that Campbell had paid the employes $60 for the move. The jury had the option of considering the value of the move, which the government said was worth about $300, as either an illegal gratuity -- a gift to a public official - or a more serious charge of bribery.

Ultimately, the juror said, the eight-woman, four-man panel agreed that since the judge had paid some money for the work, he was only guilty of accepting, and the company offering, an illegal gratuity.

Campbell was acquitted of charges that he accepted more than $7,000 in bribes from Excavation Construction in exchange for his lenient treatment of thousands of dollars of overweight truck tickets issued to the firm while he was a traffic court judge. Larry A. Campbell (no relation to the judge), an Excavation Construction official, and the company itself also were acquitted of the same charges, but convicted of offering the gratuity to the judge.

Juror French agreed that there was a point raised during the jury's deliberations that the judge had paid some money for the move. "But we thought the company had no right to make an offer like that to a public official and the public official should not have taken it," French said.

Thorp said the jury's verdict of guilty on the single count indicated the jurors felt there was an improper relationship between the judge and the construction firm.

"It was improper for a judge to take any kind of favors from anybody like that," Thorp said.

During the seven-week trial, the government also presented detailed financial evidence to show that Jenkins' requests for company funds coincided with unexplained cash deposits in former judge Campbell's bank accounts. By its verdict of acquittal on all conspiracy and bribery counts, the jury said it was not persuaded that the financial evidence backed up Jenkins' testimony, as the government had argued.

"I couldn't do it beyond a reasonable doubt, so that's it," said French.

Thorp recalled that the government had introduced into evidence the receipt that showed that Excavation Construction had paid for a rental truck to move former judge Campbell's household belongings. "There wasn't anything like that" on the other specific charges against Campbell in connection with alleged payoffs, Thorp said.

Thorp said she was not concerned that neither Campbell took the witness stand to testify during the trial. Thorp said she thought perhaps both men had testified before a federal grand jury that indicted them in August 1980, and therefore did not have to testify at the trial. In fact, the testimony before a grand jury and at a trial are unrelated.

"I thought his lawyer was testifying for him," Thorp said, referring to former judge Campbell's defense attorney, R. Kenneth Mundy.