CBS Entertainment yesterday announced major revisions in its troubled Tuesday and Wednesday night schedules . . . introducing two new comedies and a one-hour drama series, starting in March . . .

sw,-2 sk,2 ld,10 In addition, three series will move from Wednesday to Tuesday and the Tuesday night movie will become the Wednesday night movie . . .

As a result of the move, "Crazy Like a Fox" will leave the Wednesday schedule for an indefinite rest and "Trapper John, M.D." will exit the Tuesday lineup "with scheduling plans to be announced" . . .

Among the newcomers, "Fast Times," a sitcom about contemporary teen-agers and the adults in their lives, will premiere Wednesday, March 5, in the 8 p.m. time slot . . .

The series is based on the motion picture "Fast Times at Ridgemont High." The most recognizable name in the large cast is Ray Walston . . .

"Tough Cookies," starring Robby Benson as a young Chicago police detective "in daily contact with many of his old chums who opted for a life on the opposite side of the law," will debut the same night at 8:30 . . .

When Robby takes a break, it's usually at the Windbreaker, a bar run by Lainie Kazan, "a brassy lady with a heart of gold" (Captain Airwaves is pretty sure he's met Lainie) . . .

"Morningstar/Eveningstar," starring seven veteran actors as residents of a retirement home brought together with a group of youngsters who move in when their orphanage burns down, premieres Tuesday, March 25, at 8 p.m. . . .

The veterans include Mason Adams, Jeff Corey, Scatman Crothers, Kate Reid, Sylvia Sidney, Elizabeth Wilson and Teresa Wright . . .

With the changes, "Mary," starring Mary Tyler Moore, will move to Tuesday at 9 p.m., starting March 25, exiting its current Wednesday time slot as of its Feb. 26 broadcast . . .

"Foley Square" moves to Tuesday at 9:30 the same evening following a similar Feb. 26 airing . . .

In the case of both "Mary" and "Foley Square," CBS plans "special programming" in their time slots while they're off the air -- presumably to let CBS Entertainment make some much-needed changes in their current storylines . . .

Meanwhile, "The Equalizer" will move from Wednesday after the March 12 broadcast to Tuesday at 10, starting March 25, while the "CBS Wednesday Night Movies" will be introduced March 19 . . .

"Crazy Like a Fox" will bid farewell on March 12, while "Trapper John" heads for the intensive care unit March 18 . . .

* Woof!sw,-2 sk,2 ld,10 We may be barking up the wrong tree, TV Column fans, but a sharp-eyed viewer reports that in Part I of "Lord Mountbatten: The Last Viceroy," the Masterpiece Theatre series currently airing on PBS, Lord and Lady Mountbatten were seen boarding an airplane with a Sealyham terrier in tow . . .

When they deplaned in India, however, they were accompanied by a wee West Highland white terrier . . .

In Episode II, the viewer added, the Sealyham popped up again . . .

Captain Airwaves, a firm believer in reincarnation (he plans to return next time as a tree, writing a daily Treevee Column for his little friends in the forest), has a ready explanation for the switch . . .

Nevertheless, he's promised sharp-eyed viewer that he will contact the experts at Brent Walker TV Productions in London and the "Masterpiece Theatre" chaps at WGBH in Boston for their explanation of what is obviously no mystery at all to students of reincarnation . . .

According to overnights in Nielsen's 12 major markets, Part Twoski of NBC's "Peter the Great" took the battle of the mini-series Monday night (N.B., ratings story below), averaging a 20.4 rating and a 29 percent audience share . . .

Part II of CBS' "Sins" averaged a 19.8/28, while "The Gladiator" on ABC did a 14.3/20 during the same two hours, starting at 9 . . .

Our Chateau Marmont bureau chief reports that Lorimar is planning to revive the old NBC serie "Mama's Family," which was a spinoff from "The Carol Burnett Show" . . . Vicki Lawrence may be starred again in the series, which would be syndicated . . .

Channel 5 has renewed "Three's Company" through 1994 . . .

CBS News' "Nightwatch" will air a two-hour special starting at 2 a.m. Friday morning on the subject of "The Unsheltered." The study of the urban homeless will include a good deal of footage taped in Washington. Charlie Rose anchors the special, Ed Baumeister is executive producer . . .

ABC Entertainment will neither confirm nor deny, but "Diff'rent Strokes" is apparently gone after this season . . .

The Earle Palmer Brown agency in Bethesda, in cooperation with American Security Bank, has prepared a 30-second public service announcement on behalf of "The Space Shuttle Children's Fund," a nonprofit trust fund set up for the education, health, support and maintenance of the 11 children who lost a parent in the Challenger space shuttle tragedy last week . . .

Efforts were being made late yesterday to air the PSA on the three networks last night following the president's State of the Union address. Plans are to eventually distribute the appeal to the 600 network affiliates to aid in the drive . . . for which American Security is trustee and central depository . . .

Reflecting the nation's interest in the Challenger story, ratings for the three network news programs during the week ending Jan. 31 were up some 18 percent overall from the previous week's figures . . .

"CBS Evening News With Dan Rather" had a 15.5 Nielsen rating (representing an audience of 13.3 million TV homes) and a 25 percent audience share . . . up 1.6 million homes over the previous week's nightly average . . .

"NBC Nightly News With Tom Brokaw" had a 14.0/23, up 1.5 million homes for the week, and "ABC World News Tonight," with a 13.9/23, was up 2 million homes . . .

CBS had its highest rating since January 1985; NBC, its highest since February 1982 . . . and ABC, its highest since January 1982 . . .

tvrate 136.0The Cosby Show (Thurs.)51NBC232.9Family Ties47NBC327.6The Cosby Show (Sun.)40NBC423.9Dynasty34ABC523.860 Minutes37CBS23.8Cheers34NBC23.8Highway to Heaven34NBC823.6Who's The Boss?34ABC923.2Growing Pains33ABC1022.8Golden Girls37NBC1121.4Miami Vice36NBC1221.2Night Court31NBC1320.9Dallas33CBS1420.5American Music Awards30ABC1520.422733NBC1619.7Sins I29CBS1719.5Amazing Stories28NBC1819.4Knots Landing31CBS1919.1Cagney & Lacey31CBS2019.0Peter the Great I28NBC19.0Moonlighting28ABC

sw,-2 sk,2 ld,10 NBC won the week as the February ratings sweeps got under way but it was Bill the Great, not Peter, who boosted the network to a handy win over second-place CBS . . .

Two episodes of "The Cosby Show" performed considerably better than the debut of "Peter the Great" on the network Sunday night. As a matter of fact, "Peter," which looked good in the big cities, was outscored by Part I of CBS' "Sins," when the votes from the smaller markets had been counted . . .

For the week, NBC averaged an 18.2 rating and a 28 percent audience share, compared with a 16.4/25 for CBS and a 15.8/24 for ABC . . .

In other breathtaking developments during the week ending Feb. 2, NBC's "A Masterpiece of Murder" finished 28th, ABC's "Octopussy" was 31st and ABC's "The Colbys" tied for 32nd . . .

The overrun until 7:16 p.m. Sunday of the Pro Bowl on ABC tied for 36th and NBC's "Blacke's Magic" tied "St. Elsewhere" for 38th . . . as the latter's AIDS story line gave that series its highest rating (a 16.1) of the season . . .

The debut of the Disney Movie on ABC was 41st, "Kung Fu: The Movie" on CBS tied for 44th, CBS' "Mary" (see above) was 49th, CBS' "Foley Square" (see above) was 51st and CBS' "The Equalizer" (see above) was 55th . . .

ABC's "Diff'rent Strokes" (see above) was 56th, the January edition of NBC News' "American Almanac" was 59th and ABC's new "He's the Mayor" was 60th . . .

CBS' "Melba," in its one-night stand before being withdrawn, finished 62nd, while ABC's new "The Redd Foxx Show" was 63rd . . .

Both just escaped the Final Five last week, which included, in order, CBS' "Charlie & Company" in 64th, followed by four ABC series: "Ripley," "Benson," "Fall Guy" and a special "Life's Most Embarrassing Moments," which finished an embarrassing 68th among 68 programs ranked . . .

And Finally . . . In anticipation of the mid-March move from L'Enfant Plaza to new headquarters at Braddock Square in Alexandria, the 250 employes of the Public Broadcasting Service last Friday cleaned out desks, files, whatever, to get rid of old junk not worth moving . . .

Among the 11 tons of trash collected was a 1966 personnel folder. PBS was chartered in 1969 . . .