There was a new production of the play "A Raisin in the Sun" on TV the other night, kicking off PBS's traditional observance of Black History Month. The commercial networks, as is their tradition, are paying the event the same attention they pay National Library Week.

But saying it's business as usual at ABC, CBS and NBC this February doesn't mean what it would have meant five years ago, or even a year ago. Business has changed. There are signs of black progress in an area that might be more significant than PBS's one-shot dramas, documentaries about Aretha Franklin or Wynton Marsalis concerts.The signs are in weekly series programming.

Consider:

- The success of "The Cosby Show," still No. 1 in prime time, has opened the networks' schedules to a variety of black-cast comedies, from "Amen," which revolves around a black church, to "A Different World," about students at a predominantly black, Southeastern college.

- ABC's launch of "A Man Called Hawk," a crime series developed for a black secondary character in "Spenser: For Hire" who got more mail than its white star. And though the leading man in "Hawk" is a stereotype - the street-smart, Shaft-like tough guy - ABC also is getting ready to unveil what could be a breakthrough melodrama: "Gideon Oliver," which stars Oscar winner Lou Gossett Jr. as a globe-trotting archaeologist-adventurer not unlike movie hero Indiana Jones.

- Arsenio Hall, a young black comedian and actor, is vying for a slice of late-night pie with a syndicated talk show that bears his name.

- CBS' plans next month to introduce "Generations," a daytime drama that focuses on crisscrossing lives of two Chicago families, one white, one black.

Clearly, TV has come a long way since Carroll became TV's first black professional in "Julia" (1968-71), an NBC comedy-drama about a widowed nurse raising a young son.

But has TV come far enough? No.

The roster above is misleading, because there are still relatively few minority members among the characters who appear on TV daily.