NEW YORK (AP) _ A federal judge has directed that the medical records of Charlie Chaplin's late wife be disclosed to determine whether she had guaranteed a $500,000 loan to her psychiatrist in 1989.

U.S. District Court Judge Loretta A. Preska on Wednesday ordered lawyers for the estate of Oona O'Neill Chaplin to provide the records to help decide the dispute.

Mrs. Chaplin, wife of silent film legend Charlie Chaplin and daughter of playwright Eugene O'Neill, died of cancer on Sept. 29, 1991, at age 66. Her husband died in 1977.

''There's a mystery here,'' said Michael A. Lacher, lawyer for the estate. He said Mrs. Chaplin never signed such a document on behalf of Dr. Christ L. Zois, who practices in New York.

Zois also was implicated in the findings of a committee that disbarred Gloria Vanderbilt's former lawyer, Thomas Andrews. The First Appellate Division's disciplinary committee found that Andrews and Zois misappropriated Vanderbilt's money and fooled her into signing away valuable assets.

''He (Zois) seems to have some celebrity patients whose confidence were imposed upon, to say the least,'' Lacher said Thursday.

Andrews says Mrs. Vanderbilt approved his receipt of $50,000 from her and he denies wrongdoing. Mrs. Vanderbilt, known for her line of designer jeans, is descended from Cornelius Vanderbilt, who once owned the New York Central Railroad.

Lacher said Mrs. Chaplin had surgery a month before she allegedly signed the guarantee on June 14, 1989. Mrs. Chaplin's doctors say that on that date she was in a hospital in Geneva recovering from a cerebral hemorrhage.

''Mrs. Chaplin on that date certainly did not and could not have signed that guarantee,'' Lacher said.

Berkshire Bank, which provided the loan, is seeking to get the money from the estate or Zois, who has said he does not have the money to pay.

Zois did not return a call for comment on Thursday. He told The New York Times on Wednesday that he had asked Mrs. Chaplin by telephone to guarantee the loan to cover debts left from a psychotherapy center that failed. He said she did so but that he never saw the documents.