Tapes played today at the Abscam bribery trial of Sen. Harrison A. Williams Jr. (D-N.J.) depicted the senator as a willing, eager and satisfied participant in a key June 28, 1979, meeting with an FBI agent posing as an Arab sheik.

The tapes seem to run contrary to defense claims that the government agents fooled Williams into boasting of his influence. In one, Alexander Feinberg, Williams' personal attorney and co-defendant, called Mel Weinberg, an undercover FBI informant, just after the June 28 meeting to say the senator was "thrilled to death with himself" about the discussion, where he told the "sheik" there would be no problem getting government contracts for a titanium mine in which Williams would hold a hidden interest. Williams even told the sheik he would discuss the mining venture with the president.

In one audio tape played today, Feinberg said: "You know the senator seemed to get a big kick out of his own performance, because when he related to me what he said and he keeps saying after each statement 'And it's all true,' he says [laugh]. He was very excited, like a kid, he was pleased with himself."

Williams and Feinberg are on trial in U.S. District Court in Brooklyn on conspiracy and bribery charges. According to the indictment, the senator agreed to help obtain government contracts in return for a $100 million loan for the titanium venture. He allegedly held an 18 percent share he thought could be worth $12.6 million.

In his opening statement last week, Williams' defense attorney, George J. Koelzer, seemed to be laying the groundwork for a claim that the government entrapped his client. He concentrated his opening, and his cross-examination of Weinberg today, on what he characterized as the government's effort to put words in the senator's mouth.

Another audio tape played today showed that alleged co-conspirators Feinberg, Angelo Errichetti and George Katz freely joined Weinberg in preparing the senator for the rendezvous. The cases of Errichetti, mayor of Camden, N.J., and Katz, a New Jersey businessman, have been severed from this one. The tape was made the day before the June 28 meeting with the "sheik" at New York's Plaza Hotel.

With Feinberg on the phone with the senator, Errichetti is heard saying, "If you ever gave a speech in your f------ life, you better give one tomorrow." Katz chimed in, "This will probably be the most important speech he ever gave." Errichetti added, "Now you're talking command performance."

A short time later, Weinberg says of the senator: "Maybe we should give him a marijuana to pep him up [for the next day's meeting]."

"Oh, no. I'm gonna to be next to him," Errichetti said. "I got the f------ pin. He knows I got a pin next to him."

On another tape, made a week after the June 28 meeting, the unwitting Feinberg was still ecstatic in talking about it with undercover informant Weinberg. Feinberg described how he planned to accept Williams' hidden shares in the mine and then endorse them. "But I will not say to who," he said. "It will be in blank."

Weinberg: "Right, okay."

Feinberg: "Has to be that way."

Weinberg: "All right."

Feinberg: "Because as soon as you put his name in you, you, you've killed it."

Then Feinberg said of the senator, "He's happy as a lark. He can't believe it either. [Laugh] He thinks it's a fairy tale, too."

At the end of the call Feinberg told Weinberg, "Then you came down [after the meeting with the sheik] and said everything is okay and Christ, he [Williams] was as happy as a kid with a lollipop, for Christ's sake."