A Virginia judge suddenly reversed himself today and decided not to jail Norfolk reporter David Chandler for refusing his order to reveal confidential sources he used in preparing stories about apparent corruption in the state government's purchasing agency.

Richmond Circuit Court Judge James B. Wilkinson did not say precisely why he was dropping his earlier order except that a grand jury investigating the agency now has "relevant evidence" on which it can proceed.

The "relevant evidence," the judge said, did not include the names of sources that Chandler, a reporter for The Norfolk Ledger-Star, had consulted for an article that said salesmen were giving color television sets and other gifts to purchasing agents in return for state business.

The judge's order appeared to follow guidelines a Supreme Court justice suggested in a 1972 case involving a subpoena issued for a reporter's notes. In that opinion, Justice Lewis F. Powell said prosecutors and grand juries should always look elsewhere before asking a reporter to disclose confidential sources.

Chandler, 42, who led a team of reporters that won a Pulitzer Prize in 1962 for articles on corruption in Panama City, Fla., had refused to name his sources. He claimed he was protected by the First Amendment's guarantee of a free press -- an argument rejected by Judge Wilkinson.

Both the reporter and his lawyers had argued that the sources Chandler used were readily available. "I found them," Chandler said in an interview. "They didn't find me. And I've only been in the state six months."

Wilkinson had ruled last Friday that the names of the sources were necessary to the grand jury's work. He fined Chandler $1,000 a day and ordered him jailed, effective today, for his silence.

Chandler and one of his lawyers, Louis Ryan, of Norfolk, met with the judge and Richmond Commonwealth's Attorney Aubrey Davis before an open court session today, but the reporter said later they offered Wilkinson no new information about the sources or his reporting of the story.

Ryan declined to speculate on why Wilkinson changed his mind. "I think it's just a matter of the grand jury having had time to digest everything we gave them last week."

Chandler testified before the investigative panel on March 13. He said afterward that he gave the grand jurors "a lot of information I felt comfortable with." He added: 78I didn't reveal any confidential sources, but I gave them all sorts of people to check out."

Frank Caperton, executive editor of the Norfolk newspapers, was quoted by United Press International as calling the judge's action a victory. "We're certainly pleased," he said. "We have achieved both our goals: We kept David Chandler out f jail and we protected our sources."