* * 1/2 "ALL SYSTEMS GO." Donna Summer. Geffen. Not funky like Aretha Franklin's nor soulful and womanly sounding like Anita Baker's, Summer's heartfelt vocals often conjure up the image of a gangly teen-age girl with rock 'n' roll posters on her bedroom wall. That's true on the loose-limbed rock cut "Only the Fool Survives," in which her duet with Starship's Mickey Thomas just amounts to two strong voices with no place special to go. She's more effective on dreamy ballads ("Jeremy," "Fascination"), although the album's showcase track is the Richard Perry-produced "Dinner With Gershwin." Seemingly tailor-made for Summer's risk-taking persona, the song sounds like nothing else on the radio--and that's its biggest selling point. Also excellent is the jazz-tinged "Thinkin' About My Baby," a Summer-produced track that has her sounding vaguely like Rickie Lee Jones. Summer doesn't go quite far enough in exploring new musical avenues--but when she does, the results are worth the trip.