PREVIEWS OF TWO CABLE TV SHOWS

One doesn’t want to make final judgments too early, but chances are that “Sanchez of Bel-Air,” a new comedy series debuting at 8 tonight on cable’s USA Network, delivers what will stand as the single most stupid line of dialogue on television this season.

It comes at the end of the half-hour program, after well-to-do clothes designer Ricardo Sanchez has relented and said that his wife of some 18 years can go back to work. She had quit when the family moved to its swank new home two weeks earlier, but she wasn’t finding any reward in doing nothing. So he has said she can work at his company.

“Now that you’re on the payroll,” he says to her later, “can I ask you a question about your work? What exactly is it that you do?”

“Sanchez of Bel-Air” is about a Latino family--parents, two teen-age children and a grandmother--who have moved from East L.A. to ritzy L.A., where they have varying degrees of difficulty fitting in. That’s no surprise, since they can’t even get along with each other.

Created and produced by Dave Hackel and April Kelly for Paramount, one of the owners of the USA channel, this may be cable’s way of telling us that what we’ve been watching on commercial television all these years wasn’t as bad as we thought.

HBO takes a more worthy whack at comedy Saturday with “Really Weird Tales,” a series of three half-hour spoofs of anthology shows such as “The Twilight Zone” and “Amazing Stories.”

Cowritten, coproduced and hosted by SCTV alumnus Joe Flaherty, the trio of shows star three other former SCTV regulars--Martin Short, John Candy and Catherine O’Hara. The episodes are combined for the first telecast Saturday at 10 p.m., then will be split up and run separately at other times during the month.

This is the sort of stuff at which SCTV used to excel, but the two episodes available for preview--”All’s Well That Ends Strange,” with Short, and “Cursed With Charisma,” with Candy--fall considerably short of that standard. They suffer from much the same problem that often besets the shows they are parodying--an intriguing story idea that peters out instead of building to a big finish.