PUBLIC TELEVISION--Several new arrivals highlight a varied week on public TV.
Among the most promising is WNET's eight-part "Rockschool" series (2:30 p.m. Saturday on Channel 28) hosted by Herbie Hancock.
Filling in some of the gaps left by MTV, "Rockschool" explores the techniques, theory and craft behind today's music. Each half-hour episode features musicians who explore the interaction of their instruments in a rock band. John Taylor of Duran Duran and Stanley Clarke and Gary Moore of the Gary Moore Band are guests on the premiere.
Another of this week's newcomers is "The Skin Horse" (10 p.m. Wednesday on Channels 28, 15, 24 and 50), an award-winning British film about the sexual needs of severely disabled persons. Betty Rollin narrates a follow-up discussion.
And still another change of pace is provided by "Olympic Challenge" (7 p.m. Sunday on Channels 50 and 15, and 9 p.m. Monday on Channel 28), a chronicle of the various behind-the-scenes workers at the 1984 Los Angeles Olympics.