By blanketing the Apollo Theatre Foundation with subpoenas, state Attorney General Dennis Vacco has taken a bold step toward fixing the mess at the landmark hall. Now he must go all the way: Remove its inept board of directors.

Vacco's move, which includes a subpoena for Rep. Charles Rangel, chairman of the foundation and dean of the New York congressional delegation, proves the AG means business. But unless the current board is removed, it will be business as usual. And that means the Apollo will continue to deteriorate as the very people entrusted to save it look the other way, or worse.

Vacco realizes as much, which is why he has summoned all 11 members of the Apollo board to his office today. He had obtained documents about the Apollo's shaky finances but has concluded that the board has no intention of cleaning up its act.

The showdown follows several developments that illustrate just how determined the board majority is to run the Apollo like a private club instead of the state-owned gem that it is.

For example, television producer Frank Mercado-Valdes, who submitted a bid for the lucrative TV contract with the foundation for "It's Showtime at the Apollo," has complained that someone close to key board members suggested he withdraw the bid so Rangel pal Percy Sutton could keep the contract for one more year. The Mercado bid, which would have guaranteed the theater at least $2 million over four years, was vastly superior for the theater than the recently expired five-year deal with Sutton's Inner City Broadcasting. Under that sweetheart agreement, the theater got a paltry $200,000 over five years.

That's the crux of the Vacco probe: The show pulled in more than $26 million, but the theater got only $200,000, despite the fact that it was supposed to get 25% of revenues. The "Showtime" syndicator, Western International, also was supposed to get 25%, and it got $6 million. Go figure.

As this page has said, something's rotten when the theater gets so little while everybody else is getting so much.

The Apollo must get its fair share of the largess gained through its name. And that can happen only if the "Showtime" contract is competitively bid. The current board, however, seems determined to see that Sutton keeps the contract.

The loyalty to the Harlem icon is admirable, but the board's legal duty is to the theater and the taxpayers who own it. The members have the job of saving a priceless institution that has contributed so much to the culture of New York and America.

If this board can't understand that role, others deserve a chance. After all, this is the media capital of the world. A new board could assemble new talent and make the theater hum as the entertainment engine of 125th St. redevelopment.

That revival begins as soon as Vacco closes the current flop.