After the Fall: NBC Gambles on New Lineup : Television: Trying to regain the ratings lead, the network plans a prime-time schedule with eight new series--five comedies, two dramas and a reality show.

In a major overhaul, NBC on Monday announced a new prime-time lineup for fall that relies on such stars as Patti LaBelle and Malcolm-Jamal Warner and producer Aaron Spelling to rebuild the ratings of the slipping network in the post-Cosby era.

NBC, which lost its six-year network leadership to CBS this season, has scheduled eight new series--five comedies, two dramas and a reality show--and is focusing heavily on rebuilding the two nights that have carried the network: Thursdays, which was powered by the departing “The Cosby Show,” and Saturdays, where the longtime smash “The Golden Girls” was dropped.

Moving into the key Thursday leadoff slot where “Cosby” held sway will be the successful spinoff of that series, “A Different World.” It will be followed by one of the new comedies, “Rhythm and Blues,” in which a black radio station is about to add a white disc jockey.

The station owner in “Rhythm and Blues” will be played by Anna Maria Horsford, the wallflower daughter of “Amen.” Also featured is Ron Glass, one of the detectives in “Barney Miller.”

NBC is sticking with the remainder of its key Thursday lineup: “Cheers,” “Wings” and “L.A. Law.”

On Saturdays, meanwhile, two new comedies will open the night, starting with “Here and Now,” produced by Cosby and starring Warner as a graduate student in psychology who works with “economically disadvantaged kids” at a Manhattan youth center. Warner formerly played the son Theo in “The Cosby Show.”

Following the new Warner series on Saturdays will be “Up All Night,” which stars LaBelle as the overly maternal owner of a dance club and apartment building who takes a young man under her wing and gives him a managerial position in her business.

Warren Littlefield, the president of NBC Entertainment, said in announcing the schedule that his goals included a transition from trying to win the largest number of viewer households “to demographic focus.”

CBS is the only major network that still places the highest priority on attracting the widest possible audience, yet it also won the key demographic competition this season.

Spelling, meanwhile, is delivering to NBC what is described as a twentysomething type drama, “The Round Table,” about “the lives of a diverse group of young professionals” in Washington who “pursue careers in lawmaking and law enforcement.”

With NBC also letting such dependable ratings entries as “In the Heat of the Night” go to CBS and “Matlock” to ABC, Littlefield emphasized that his network will still attempt to be the leader in “quality drama.”

Admirers of NBC’s “I’ll Fly Away,” a brilliant new series set in the South as the civil rights movement emerged in the 1950s, will surely be pleased that it made it back for the fall, despite borderline ratings. However, it has been given an almost deadly time slot--10 p.m. on Fridays.

Another solid drama series, “Reasonable Doubts,” has also been given a new, killer time slot: 9 p.m. Tuesdays, opposite ABC’s “Roseanne” and “Coach.” And still another NBC drama, “Quantum Leap,” is in somewhat the same position, being switched to 8 p.m. Tuesdays, opposite the ABC smash “Full House.”

NBC’s best drama, “Law & Order,” one of the finest series in years, has been moved again, to 10 p.m. Wednesdays. But it has successfully taken its audience with it in the past.

With election time coming up, NBC has also brought back Norman Lear’s sitcom “The Powers That Be,” which stars John Forsythe as an amiable but not too bright senator surrounded by his ambitious family and political staff.

Under the regime of its tight-fisted parent company, General Electric, NBC keeps pressing in all possible areas to maximize its financial performance. When Johnny Carson retires on Friday from “The Tonight Show,” which he owns, the series, a big moneymaker, will revert back to NBC. In addition, three of the eight new series in the fall schedule are either wholly or partly owned by NBC. They are: “Up All Night”; “Secret Service,” a one-hour anthology drama that will be based on “the files of the Secret Service,” and “I Witness Video,” a one-hour reality series using camcorder footage of unstaged events.

Several editions of “I Witness Video” have aired this season, and in the fall it will be scheduled on Sundays at 8 p.m. against another video series, “America’s Funniest Home Videos,” and “America’s Funniest People,” both on ABC, and presumably CBS’ “Murder, She Wrote,” although that network has yet to announce its new prime-time lineup.

NBC’s two other new series are:

* “Loved by You,” starring Paul Reiser (“My Two Dads”) and Helen Hunt in a comedy about a young married couple who live and work in Manhattan.

* “In the Loop,” with David Keith and Bill Nunn as former high school friends and football teammates who are thrown together again by circumstances. Nunn, divorced, owns a gas station/mini-mart, and Keith, just out of prison, “shows up on his doorstep.”

NBC series from this season that failed to make the fall lineup include “The Adventures of Mark and Brian,” “Pacific Station,” “Man of the People,” “Flesh ‘n’ Blood,” “Dear John,” “The Torkelsons,” “Real Life With Jane Pauley,” “Expose,” “Night Court,” “Eerie, Indiana,” “Walter and Emily,” “Hot Country Nights,” “Mann & Machine,” “Nightmare Cafe,” “The Fifth Corner” and “Against All Odds.”

However, NBC says that several of these series, possibly including “The Torkelsons” and “The Fifth Corner,” might return, and that “Hot Country Nights” might have future outings as specials.

With NBC constantly the subject of rumors that it might be sold, in part or whole, by GE, all eyes in the TV industry will be on its performance this fall. Sliding downward, it averted going from first place to last by only a tiny fraction of a rating point this season.

Only one of NBC’s seven comedy series that debuted last fall, “Nurses,” has made it back on the new lineup. While both of last fall’s new dramas, “I’ll Fly Away” and “Reasonable Doubts,” earned return shots, comedy series are widely regarded as the primary source of program profits.

Here is NBC’s night-by-night schedule:

* Monday: “The Fresh Prince of Bel Air,” “Blossom,” “Monday Night at the Movies.”

* Tuesday: “Quantum Leap,” “Reasonable Doubts,” “Dateline NBC.”

* Wednesday: “Unsolved Mysteries,” “Seinfeld,” “Loved by You,” “Law & Order.”

* Thursday: “A Different World,” “Rhythm and Blues,” “Cheers,” “Wings,” “L.A. Law.”

* Friday: “In the Loop,” “The Powers That Be,” “The Round Table,” “I’ll Fly Away.”

* Saturday: “Here and Now,” “Up All Night,” “Empty Nest,” “Nurses,” “Sisters.”

* Sunday: “Secret Service,” “I Witness Video,” “Sunday Night at the Movies.”