Findings on Gap Do Not Match Woods's Story

The depression of a tape recorder's "record" button on at least five different occasions caused the 18-minute gap in one of the subpoenaed Watergate tapes, technical experts testified yesterday at a court hearing before District Court Judge John J. Sirica.

The experts' findings apparently contradict the testimony of President Nixon's personal secretary, Rosemary Woods, who told Sirica last November that she had accidently erased five minutes of the tape.

The missing portion contains a conversation on June 20, 1972, between Nixon and H. R. Haldeman, then White House chief of staff. According to notes taken by Haldeman of the meeting, the two discussed the Watergate break-in, which had occurred three days earlier.

The experts told Sirica that, based on electronic evidence, they found "conclusively that the 18-minute section could not have been produced by any single, continuous operation."

Marks Left

The experts made their findings in part from marks on the magnetic tape showing that both the record button and any one of four other buttons had been pushed.

"Hand operation of keyboard controls...was involved in starting and stopping the recording of each [blank] segment," the experts said.

Woods testified in November that she had inadvertantly erased five minutes of tape by holding her foot on the recorder's "play" pedal during a phone conversation, which had interrupted a transcribing session.

The experts said the buzzing that replaced the conversation originated in noise picked up from the electrical power line to which the recorder was connected. A White House lawyer had speculated previously that Wood's typewriter and lamp caused the noise.

White House lawyer James D. St. Clair said that the experts were not qualified to testify whether or not the gap was caused by accident. He objected successfully to any questions asking if the gap could have been caused inadvertantly.

The experts were part of a six-man group which has been examing the gap since December. They submitted their report on the tapes to Sirica last weekend.

The White House issued a statement yesterday saying it would withhold immediate comment, as "any premature comment would only contribute further to existing public confusion surrounding the tapes."