"The 1/2 Hour Comedy Hour," a summer series premiering on ABC tonight, tries to cram two minutes' worth of laughs into a 30-minute time slot. As might be expected, that leaves a lot of rattling-around room. The sum total fails to equal the sound of a single "ha."

Dick Clark and Chris Bearde produced the program, which airs at 8 on Channel 7 and proves a limp reworking of the old "Laugh-In" format, replete with a pair of semi-amusing cohosts at the center: Thom Sharp and Arsenio Hall. Since Sharp is white and Hall is black, all their jokes revolve around the idea that the white fellow is a hopelessly dull square and the black man a sly, streetwise hipster.

Thus when Hall says "Gimme five," Sharp reaches into his pocket for a wallet and says, "I can let you have five, sure." Television achieves equality: a WASP stereotype to balance the black stereotype, and everybody loses. Once you've heard their first exchange of quips, every joke becomes predictable, although that doesn't stop a studio audience of feckless yelpers from cheering and roaring their wee heads off.

When the white guy says that with two rakes in his garage, "I'm set for life," the audience actually applauds. Surely they all had to be tied to their seats to keep them from leaping up in standing ovation.

Short skits that seem laboriously long (an "A Team" spoof called "The T Team") are interspersed with guest-star cameos (Henny Youngman, borrowing a Rodney Dangerfield joke about a psychiatrist, and Burt Reynolds, among a few others), topped off with a visit to the "Rock Bottom Cafe," which is embarrassingly similar to the old cocktail party segment of "Laugh-In."

People have complained that the NBC summer comedy series "The News is the News" isn't very funny, nor its topical satire very devastating, but at least the show is live, and brash, and gets off a zinger or two each week (and though host Simon Jones seems smugly priggish, juggler-humorist Michael Davis is the most assured TV natural to pop up since the debut of Eddie Murphy). And "News" is connected to something. The 1/2-witted "Comedy Hour" is pure polyester, abrasively and crudely synthetic.

At the ABC television laboratory, technicians work endlessly to come up with new substitutes for entertainment. "The 1/2 Hour Comedy Hour" is but the latest failure in that lamentable quest.