CBS, which finished third in primetime for the third year in a row this spring, announced some wholesale changes in the fall 1990 schedule released yesterday ...

CBS will introduce seven hours of new programs, including four sitcoms and five dramas, leaving only its Sunday and Tuesday (movie nights) lineups intact. In addition, the network is also adding NBC's reject, "The Hogan Family" ...

While CBS is giving drama a slight edge in its new schedule, an edgy number one NBC last week announced nine new shows covering six hours for its fall lineup, including six sitcoms. A challenging ABC announced six new series, including four sitcoms among its four hours of new shows ...

CBS will have new programs in the key 8 p.m. spot on five nights next fall, four of which are dubbed by CBS Entertainment president Jeff Sagansky "engaging family comedies with break-out star potential." CBS, he said yesterday, wants to broaden its demographic base to attract more family viewing in the first hour ...

The CBS fall schedule, with new programs in boldface and (NT) for "new times" for returning shows:

Monday: "Uncle Buck" at 8; "Major Dad" (NT) at 8:30; "Murphy Brown" at 9; "Designing Women," 9:30; and "Face to Face With Connie Chung" (NT) plus another NT for "new title" at 10 ...

Tuesday: "Rescue 911" at 8 and Tuesday movie at 9 ...

Wednesday: "Lenny" at 8; "Doctor, Doctor" (NT), 8:30; "Jake and the Fatman" at 9; and "WIOU" at 10 ...

Thursday: "The Flash" at 8; "The Hammersmiths" at 9; and "Knots Landing" at 10 ...

Friday: "Evening Shade" at 8; "Bagdad Cafe" (NT), 8:30; "Over My Dead Body" at 9; and "Dallas" at 10 ...

Saturday: "Four Alarm Family" at 8; "The Hogan Family" (NN for "new network" for this former NBC entry), 8:30; "The Green Machine" at 9; and "48 Hours" (NT) at 10 ...

Sunday: "60 Minutes" at 7; "Murder, She Wrote" at 8; Sunday Movie at 9 ...

If you'll all stop wiggling there in the back row, here are brief descriptions of the new shows:

Uncle Buck stars Kevin Meaney in the John Candy movie role as an ill-mannered, irreverent uncle who becomes the head of a family composed of his late brother's three kids ...

Lenny stars Lenny Clarke as a "blue-collar guy ... who's always got an answer for all of life's problems." Lenny has a loving, supportive wife (Lee Garlington) and three daughters ...

WIOU stars John Shea as a young news director sent by a network to pull WNDY, "a fading big city station, out of the ratings hole." He inherits the usual lineup of on-air and production eccentrics. Echoes of CBS's "Murphy Brown" and "WKRP in Cincinnati" here, to say nothing of TV's never-ending fascination with itself. Remember: WIOU producer Grant Tinker once caught the lightning in a bottle with his "Mary Tyler Moore Show" ...

The Flash is a one-hour action-adventure drama "based on the classic comic book about a reluctant hero with superhuman speed." John Wesley Shipp plays the "brilliant forensic scientist whose sheltered life ends forever when a bolt of lightning crashes through his crime lab in Central City," soaking him with chemicals. That could do it. The death of his police officer brother at the hands of a "rampaging motorcycle gang" turns him into a relentless crime fighter, who gets help from research scientist Amanda Pays ...

The Hammersmiths are a "large, boisterous" Pacific Northwest family headed by Lucie Arnaz, a single professional raising an adopted Korean daughter who shares the house with her happily married sister, her hubby and their three kiddies ...

Evening Shade stars Burt (I'll get it right one of these days) Reynolds as a former pro football player who returns to his hometown of Evening Shade (hence the title), Ark., to coach the high school team. The move forces his father-in-law, the local newspaper publisher, to move into a guest house on his own estate, one more reason why Dad has never forgiven Burt for marrying his daughter ...

Over My Dead Body stars Edward (The Equalizer) Woodward in a one-hour "murder mystery with a dash of comedy." He plays a burned-out crime novelist with a vague Scotland Yard background (you've got to explain that accent somehow) who works with Jessica Lundy, "an offbeat obituary writer" for a San Francisco newspaper ...

Four Alarm Family stars Gregory Harrison as a fireman widower who is raising four kids ...

The Hogan Family still stars Sandy Duncan ...

The Green Machine promises to be the CBS sales department's very favorite show, a one-hour drama about "a diverse group of top-notch professionals who have been specially selected to fight against threats to the world's ecological balance." They're led by Dr. Gil Gerard, whose surgical skills have been "honed in combat." His team also includes nuclear physicist Clayton Rohner, who gave it all up to devote himself to "righting environmental wrongs," rebel zoologist-anthropologist Robert Knepper and the "strikingly beautiful" group coordinator, Joanna Pacula ...

Among the series that will be missing next September on CBS will be "Newhart," "Falcon Crest," "Paradise," "Tour of Duty," "City" and "His and Hers" ...

"Wiseguy" is lingering in the wings as a mid-season replacement, along with a new drama starring Sharon Gless called "The Trials of Rosie O'Neill," a half-hour animated comedy from Steven Spielberg called "The Family Dog," a half-hour comedy based on the motion picture "Big," the live-action, animated half-hour "The Pink Panther" and "Sunday Dinner," a sitcom from Norman Lear ...

Sagansky said yesterday CBS is still in discussion with the producers of "Paradise" ...

Now The FOX Facts

The ever-stronger Fox Broadcasting network unveiled a five-night, Thursday-through-Monday fall schedule with nine new programs yesterday ...

The big Fox news, aside from its addition of two nights to its long weekend lineup, is the move of its big Sunday night animated hit, "The Simpsons," to Thursday, where it will be pitted against NBC's number one "The Cosby Show" as the anchor of its new lineup that night ...

Here are the nightly schedules ...

Thursday: "The Simpsons" (NT) at 8; "Babes" at 8:30; and the one-hour "Class of Beverly Hills" at 9 ...

Friday: "America's Most Wanted" (NT), expanded to an hour, at 8; and the one hour "D.E.A." at 9 ...

Saturday: "Fox Video Hour" (an expanded version of a reformatted "Totally Hidden Videos") at 8; "Cops" (NT) at 9; and "American Chronicles" at 9:30 ...

Sunday: "True Colors" at 7; "Parker Lewis Can't Lose," 8:30; "In Living Color" (NT); "Get a Life," 8:30; "Married ... with Children" at 9; "Good Grief," 9:30; and the one-hour "Against the Law" at 10 ...

Monday: "Fox Night at the Movies," 8 to 10 ...

The newcomers, several of which obviously are still missing cast members:

Babes follows the "humorous exploits of three sisters sharing a cramped apartment and struggling to make ends meet in New York City." With Susan Peretz, Wendy Jo Sperber and Lesley Boone ...

Class of Beverly Hills is a drama about an average Midwestern family, moved to America's richest community, and the impact of high school on two teenagers (Shannen Doherty and Jason Priestly). Spare me ...

D.E.A. "chronicles the life and death battles waged by our country's newest heroes" in the Drug Enforcement Administration (hence the title) ...

American Chronicles is from David ("Twin Peaks") Lynch and is described as "a breath-taking video/novel of our country's most extraordinary people, places and events." Oh-oh ...

True Colors is an ensemble comedy about an interracial couple in their second marriage. He's black and has two teenage sons. She's white, with a teenage daughter and an opinionated mother (Nancy Walker) ...

Parker Lewis Can't Lose stars Corin Nemic as "the coolest kid in high school," whose "ingenuity and devious charm elevates the wild 'n' crazy days of high school life for himself and his friends to a much higher level"...

Get a Life stars comedian Chris Elliott as "a 30-year-old paper boy who lives atop his parents garage and finds enjoyment and humor taking on some of life's less stressful situations" ...

Good Grief deals with two brother-in-law undertakers, "one of whom is less than scrupulous" ...

Against the Law stars Michael O'Keefe as an "unpredictable, unorthodox and uncouth" lawyer who is "committed to seeing that justice is done," even if "sometimes the only way to beat the unfair system is to fight a little dirty." Can the ABA sue? ...

Fox Night at the Movies will feature both theatrical and made-for-TV feature films and novels for television ...