A hockey fan who had spent the past year in New Guinea without a smidgin of sports news might wonder if he had ever been away. The Stanley Cup semifinals begin this weekend and the pairings are the same as in 1976 - New York Islanders at Montreal and Boston at Philadelphia.

Two of the four preliminary-round series and three of the four quarterfinals were reruns, too, and in each case the 1976 winner came through again. There is no sound reason to expect the semifinals to be any different.

The Islanders, who visit Montreal tonight, were the only team to win a playoff contest from the champion Canadiens a year ago. They captured the fourth game of the semifinals at Nassau Coliseum and, realistically, one victory is maximum potential this time.

The Bruins, who invade Philadelphia Sunday night, opened with a Spectrum suces last year, then dropped four in a row. Boston seems tougher this time and it would not be surprising if the series required the seven-game limit.

Here is a rundown on the semifinalists: New York Islanders at Montreal

Montreal has lost Pierre Bouchard with a shoulder separation and another defenseman, Guy Lapointe, is nursing a bruised back. There is no need to extend sympathy to the Canadiens, however, Jim Roberts can move capably to the backline from his role as a checking right wing and Nova Scotia farmhand Brian Engblom would be a regular on any other team in the NHL.

If the Canadiens have a genuine problem, it would be a lack of sharpness. They have played only four games, all noncompetitive routs of St. Louis, since ending the regular season in Washington April 3.

New York is defensively oriented and that defense has been formidable in six playoff games, permitting only 13 goals. The man in the nets in every one was Billy Smith, brother of the Washington Capitals' unsung hero, Gord.

Billy Smith, the No. 2 man to Chico Resch, was given a starting opportunity against Chicago and has played so well that Resch, best regular-season goalie outside Montreal with a 2.28 average, can't get his job back. Resch should receive an opportunity before this series is finished, however. It would take Resch and Smith playing at the same time for New York to upset a team it couldn't beat in four meetings this year.

Radio: if you're a Francophone, dial 700. Otherwise, take pot luck and spin the dial for a CBC pickup. Boston at Philadelphia

The Bruins were the hottest name on ice a week ago, but they were cooled by Los Angeles' Rogie Vachon and dropped tow straight before earning that 4-3 wrapup decision on the caost Thursday night.

Boston had won its last five regular-season games as well as three straight from the Kings. Until Los Angeles' resurgence, Boston's most recent loss had been a 6-2 thumping at Boston Garden March 24, administered by the Flyers. Boston's only victory in four regular-season meetings with Philadelphia came at the Spectrum, a pretty good indication that home ice is not an important item in this series. In fact, with visitors having won 16 of 30 games so far, it appears it is not a significant factor in playoff hockey.

Philadelphia came back scratching like a cat with an extra life, after dropping two straight home games to Toronto in the quarterfinals. The Flyers needed two implausible comebacks to even the series, then resumed their old intimidating ways to conquer the Leafs.

Four Flyers - Ross Lonsberry, Moose Dupont, Gary Dornhoefer and Paul Holmgren - face automatic one-game suspensions should they draw another game-misconduct penalty, in the playoffs. This specter, however, is unlikely to serve as much of a restraining influence.

A year ago, Wayne Stephenson replaced Bernie Parent in the Flyers' nets after the Bruins' opening victory and went the rest of the way. This year, Stephenson's relief call came early, in the quarterfinals, and Parent, booed by the Spectrum fans who once loved him, is eager for an opportunity to atone.

Radio: 1030 loud and clear, 1210 reception good but occasionally impeded by static and a partiasn approach.