During the May 16 primary, Allegheny County will deploy new voting machines for the first time in more than 40 years.

At least, they're almost "new." And some may have to be shared with counties in Tennessee.

To meet a strict federal deadline, Nebraska-based Election Systems & Software Inc. is supplying Allegheny County with 1,278 "pre-owned" touch-screen machines, according to a purchase order approved last month.

The county will have a total of 2,628 ES&S iVotronics in place for the primary, or two machines per voting precinct.

County officials have been thoroughly testing every unit, said Kevin Evanto, a spokesman for county Chief Executive Dan Onorato.

"In order to get 2,600 machines, some are being borrowed from other jurisdictions," he said. "But come November, we will have 4,700 new machines that will be owned by Allegheny County."

Before then, the purchase order says, "ES&S reserves the right to borrow all or part" of the county's fleet of machines for an Aug. 3 primary in Tennessee.

Local governments nationwide are rushing to meet the requirements of the Help America Vote Act, a wide-ranging law passed by Congress after Florida's 2000 presidential election debacle.

Under that law, known as HAVA, many counties are using millions of dollars in federal aid to replace their aging voting systems with high-tech machines like the iVotronic, which resembles a bank ATM.

But only a few companies produce voting equipment, and, to meet this year's high volume of demand, some companies keep shifting their machines around the country.

In February, Allegheny County officials approved a tentative deal with Sequoia Voting Systems, a California company, that would have brought 2,000 used electronic push-button machines here from Clark County, Nev., home of Las Vegas. The Nevada county then would have received thousands of almost-new touch- screen machines from Chicago and Cook County, Ill.

But Allegheny County dropped out of that deal last month when the Sequoia machine flunked a Pennsylvania certification test.

On April 5, Mr. Onorato announced a $11.9 million contract with ES&S for 4,700 iVotronics.

More than 20 Pennsylvania counties -- including Beaver, Butler, Cambria, Greene, Mercer and Westmoreland -- also have selected the iVotronic, which has received both state and federal approval.

Because of the looming primary election, Allegheny County officials agreed to temporarily accept some used machines.

"They'll probably come from a combination of locations," said Ken Fields, an ES&S spokesman.

Mr. Evanto said the county already has more than 2,600 machines in a warehouse on the North Side.

"They're all here. They all went through acceptance testing," he said. "Everything is going smoothly and the machines will be ready to go."

This weekend, county officials will conduct a mock election involving every machine, and they're continuing a major education campaign for poll workers and voters.

A schedule of voting machine demonstration sessions is on the county Web site: www.county.allegheny.pa.us.

As a backup for the primary, the county is printing fill-in-the-blank optical scan ballots, which voters can use if they encounter long lines at polling precincts. In November, only touch-screen machines will be used.

ES&S is still completing contracts with some Tennessee counties, according to Brook Thompson, the state's coordinator of elections.

About 15 of the state's 95 counties likely will use the iVotronic. Mr. Thompson said he was aware that machines may be borrowed from Pennsylvania.

"We are in discussions with ES&S about that as we speak," he said.

All machines will be returned to Allegheny County by Sept. 8. The company will conduct maintenance checks before bringing them back.

Mr. Evanto described the loan as a "onetime" deal.

"We're borrowing machines. So it's only fair that we offer to share ours in return," he said. "If we didn't have a lot of faith and confidence in ES&S, we wouldn't agree to that."

The company's machines performed satisfactorily during Ohio's primary election on Tuesday, said James Lee, a spokesman for the secretary of state's office. Some isolated incidents stemmed from poll worker mistakes, not technical problems.

"It went really well. We're very pleased," Mr. Lee said.