IT SHOULDN'T BE too much just once every 30 years or so to ask for an enlightened black image. You keep hoping one day to switch on the tube and find a black professor, lawyer or somebody who presents himself intelligently -- just anything other than fat, wisecracking maids and bonehead hucksters.

But apparently, Americans still are comfortable only with blacks who make them laugh. So we continue to embrace only unintelligent, comedic black images; the latest and most popular being Mr. T, the mowhawked, monosyllabic savage who embodies all the sterotypes many blacks hate to see portrayed.

This minute, Mr. T is the most visible black man in America. After his role in "Rocky III" and a few months as a star of "The A Team," he has become hot enough to appear on the cover of People magazine.

Bulging muscles, gaudy gold chains, next to no clothes and short bursts of semi-speech. T is half-man, half-animal who looks like a slave and operates on intimidation. The man with the biggest muscles makes the rules. Some bad nigger, this Mr. T. The role doesn't allow him to challenge whitey with intellect, so he'll be just as happy kicking ass.

It would be nice to think that Americans are sophisticated enough to look at Mr. T as an implausible cartoon; to think that he's just a rags- to-riches ex-bouncer who makes a living with this stupid gimmick. The danger is, however, that too many people think Mr. T is somewhat reflective of black America.

There is little if any balance in television characters to show the difference. There's Fred Sanford, the junk dealer, bluffing his way through life. There's Florence, the maid, threatening anyone within reach. There's Benson, no matter how smart, still basically a butler. And now, there's Mr. T, telling People Magazine, "It takes a smart man to play dumb." Americans must not be ready to accept a black economist, wearing bifocals, coat and tie, walking down Wall Street and speaking intelligently. Maybe having a black editor on Lou Grant would have been too threatening.

It was particularly disturbing the other day that a youngster on 14th Street would express his admiration for Mr. T, then denounce Michael Warren, a talented black actor who plays a role too small in "Hill Street Blues."

Talk to a class of 6th graders at Burnside Elementary School in Chicago (where T grew up) and 29 of 31 will say they watch "A Team," because he's tough, he can beat anybody, he doesn't take any stuff, he talks cool, he wears a lot of gold.

It's an act that shouldn't be bought. Mr. T tells kids to stay away from drugs and in school and other things that are healthy and meaningful. Unfortunately, while the voice is saying one thing, the image is saying another. At some point in the near future, I hope, I'll be able to sit down and watch Mr. T, laugh and not be concerned that people will look at this man and think one image somehow reflects so many people. But as long as T's image is basically the only one blacks are allowed to project, I won't watch; just sit back and pity the poor fool.