The 25-year-old Boeing 747 that blew up off Long Island Wednesday evening had "routine'' repairs to an engine cable and a cockpit indicator light during its three-hour turnaround at Kennedy Airport after a flight from Athens, an investigator said yesterday.

"Really routine stuff,'' said the federal investigator, who declined to be identified. "They weren't problems that would make a plane blow up.''

According to records from the Federal Aviation Administration going back seven years, the Boeing 747-100 had no history of unusual maintenance problems. Mark Abels, a TWA spokesman, said at a news conference yesterday there had been no operational problems with the plane outside the norm.

The plane was originally delivered to Eastern Airlines on Oct. 27, 1971, and was transferred to TWA four days later according to Avmark Inc., in Lolo, Mont., a firm that tracks airplane registrations. In December, 1975, the plane was sold to the Iranian Air Force, but was never delivered to that country and sat on the ground for a year. TWA repurchased the plane in December, 1976.

The airplane is one of the older 747s in service and was the 153rd of the model to roll off Boeing's assembly line in Seattle. Since then, more than 900 747s have been built, and most of the early-model planes are still in service. At the time of the crash, TWA had 10 747s, operating nine at any given time, according to Avitas, an aviation consulting firm.

From January, 1989, through the beginning of this month, TWA reported to the Federal Aviation Administration the repair of 42 maintenance problems on the craft that crashed, ranging from an emergency exit light that wasn't functioning to two instances of engine problems during flight.

The number of incident reports for the plane that crashed was not high, a spot check of other Boeing 747s in TWA's fleet indicated.

Joseph W. Queen contributed to this story.