Yana Paskova for The New York Times Charles Rangel at Friday’s news conference.

In his first news conference since learning his fellow lawmakers would put up him on trial for ethics violations, Representative Charles B. Rangel urged his constituents and the press to be patient, saying he would not address the specifics of the charges against him until the proceedings begin next week.

But Mr. Rangel, who snapped at reporters in Washington on Thursday, appeared determined to strike a softer tone at Friday’s appearance, even offering a public apology to one reporter, Luke Russert, whose question on Thursday — about whether the charges would cost the congressman his job — Mr. Rangel dismissed as “dumb.”

He suggested several times that he had decided to hold the news conference despite the advice of his lawyers and aides and that all the facts would be aired before the Sept. 14 primary.

“I’m in the kitchen and I’m not walking out,” Mr. Rangel insisted.

But when asked about the charges against him, Mr. Rangel parried with rambling reflections on the awkwardness of the situation and the pain the investigation had inflicted on him and his family.

“I cannot go beyond this statement because I am here to tell you something awkward,” Mr. Rangel said. “The investigation is over. Come Thursday, we will be talking about the allegations.”

Mr. Rangel, 80, appeared on his political home turf one day after a House investigative panel announced that he would face a public ethics trial over findings that he had violated a range of ethics rules. While the panel did not disclose details of those violations, officials with knowledge of the investigation have said that they involve Mr. Rangel’s acceptance of four rent-stabilized apartments in Manhattan and efforts by his office to preserve a half-billion-dollar tax break for an oil executive who pledged a donation for an educational center being built in Mr. Rangel’s honor.

The charges capped a two-year investigation that forced Mr. Rangel — revered by many people in Harlem — from his powerful perch as chairman of the House Ways and Means Committee, made him the poster boy for Republican attacks on House Democrats, and drew campaign challenges from several fellow Democrats now eying his seat.