"No Soap, Radio" is another all-out assault on the funny bone that fails to result in a compound fracture. But at least this ABC comedy, produced by TV veteran Mort Lachman, takes a stab at being different; it's a studiously oddball freefall that definitely has its moments.

The comedy airs tonight at 8 on Channel 7, which is something of a tiny tragedy in itself. ABC insists on using this time slot--in which it has not been competitive for about two years--to try out promising projects that don't stand much of a chance against the powerhouse "Magnum, P.I." on CBS. So they fail to earn big ratings, and ABC crumples them up and callously throws them away.

This was the vicious fate that befell the dear departed "Police Squad!", a truly funny, wildly welcome sendup of cop-show cliche's and TV cliche's in general. ABC ordered six episodes for a test run, but has only aired four of them; the network yanked the last two from the schedule without warning and aired new editions of the abysmal "That's Incredible!" instead. That's not so incredible. That's just the way they do business at ABC, the network of the Philistines.

"No Soap, Radio" attempts to impose hellzapoppish gags and blackouts on a primitive sitcom story line--the saga of Atlantic City's rundown Pelican Hotel, the kind of dump where water drips continuously on the registration desk, a Teutonic midget does six-floor drops with the elevator, and a crafty, crybaby lawyer schemes to take over the joint on behalf of the Tarantula Brothers, Joey and Nick, who want to tear it down and erect a shrine to the god of parking.

At any given moment, and at some not-so-given, the story gives way to outrageous, absurdist sketches. These involve a little boy with a basketball head, a lethal box of Raisin Flakes, a scandalous confession by Elmer Fudd, and a bulletin on the whereabouts of Mr. Potatohead.

Even when the sketches make suds, the transitions leading into and out of them are deft, even marvelous--so clever they recall the hysterically halcyon days of "Monty Python's Flying Circus." Credit for this goes to the show's four writers, director John Robins and editor Larry Harris; they made "No Soap, Radio" technophrenically telegenic.

The hotel portions might be negligible if not for the high caliber of performers involved. Steve Guttenberg is the manager--wearing the pliantly likable kisser with which he is currently brightening the movie "Diner." The other residents include Bill Dana, Fran Ryan and Stuart Pankin. Also popping up briefly in the mayhem are treasurable souls like Edie McClurg, Jack Kruschen, Gary Owens ("We'll be right back after this." "We're back.") and, as a dirty old bum who rattles off a little Mozart, Sidney Miller, Donald O'Connor's costar from the TV '50s.

You have to admire this many talented people daring to prance out on a limb, even if the limb is clearly too spindly to support them.