‘SISTER SAM’ SHOWS PROMISE

The premiere of “My Sister Sam” at 8:30 tonight on CBS (Channels 2 and 8) is mildly amusing and fetching enough to invite a second look.

That’s a big improvement over the unaired original first episode, in which San Francisco free-lance photographer Samantha Russell (Pam Dawber) has her obnoxious teen-age sister Patti (Rebecca Schaeffer) foisted upon her. The new premiere’s setting, premise and characters are the same, except that Patti is far less shrill and the show is softer and funnier.

This doesn’t promise to be a sitcom to center your evening on. Yet tonight’s story offers some moderately snappy writing by Gary Murphy and Larry Strawther and an appealing sibling relationship that may be worth following.

There’s a minor crisis when Patti’s clanking-metalloid, pointy-haired punk boyfriend, Brandon (Dean Cameron), gets a crush on Sam, causing tension between the sisters. Brandon bawls when Sam tells him it won’t work. “Don’t cry,” she says. “You’ll rust your glove.”

Play it again, Sam.