For the second time in less than a week, Allegheny County's Board of Elections has delayed a final decision on buying thousands of touch-screen voting machines.

Board members had a deadline of yesterday to approve a contract with Diebold Inc. of North Canton, Ohio, for 5,600 touch-screen machines at a discounted price of $11.9 million. But the company has granted an extension until Tuesday.

But voting activists who packed a three-hour public hearing at the county courthouse, Downtown, called on the elections board to consider alternatives to Diebold's AccuVote-TSX because of concerns about the machine's computer coding and its lack of a paper printout that allows voters to check their choices.

One activist, Richard King, of Squirrel Hill, said he and a group of voters plan this week to file a lawsuit against the county to block any purchase of new machines. They want to give the state Legislature time to pass a bill that would mandate the use of machines with paper printouts.

Yet county officials don't see further delay as an option. Local governments across the country are scrambling this year to obtain voting machines that meet the requirements of the federal Help America Vote Act, a law that grew out of the disputed 2000 presidential election in Florida.

Under that law, Allegheny County risks losing $12 million in federal aid if it doesn't have new voting machines in place by the May primary election.

County Chief Executive Dan Onorato said the U.S. Department of Justice also may fine the county if it doesn't replace its lever machines, in use since the 1960s.

The elections board will reconvene at 2 p.m. Tuesday.

"The county is going to make a decision," said Mr. Onorato, a Democrat, who sits on the board with County Council's two at-large members, Republican Dave Fawcett and Democrat John DeFazio. "We've looked at this for months."

But he offered to review the issue for another week.

Mr. DeFazio expressed frustration at the county's limited options.

That's because Diebold is the only company that has promised to deliver state-certified machines within eight weeks, according to Tim Johnson, director of the county Department of Administrative Services.

Some voting activists yesterday said they prefer machines that use ballots resembling standardized tests, allowing voters to fill in ovals for each choice.

Several of the machines, known as optical scanners, have been certified by the state, but county Elections Director Mark Wolosik said paper ballots can't be used easily by some disabled voters, a requirement of the law.

Also, the ballots are expensive.

"We'd have to print a million ballots every election," Mr. Wolosik said.

David A. Eckhardt, a lecturer in the computer science department at Carnegie Mellon, said there still are many questions about the reliability of software used by touch-screen computer machines.

"Voters should not place confidence in unknown software," he said.

He told board members that, in California, Diebold installed new software on some machines that was never certified by state officials.

David Bear, a spokesman for Diebold, said none of the changes was substantive.

"Those kind of changes didn't need certification," he said, noting that Pennsylvania officials always would be able to test equipment.

At yesterday's meeting, Angela Chan, the county's deputy director of administrative services, said officials had considered issues surrounding Diebold and were satisfied with the company's performance elsewhere.

"Obviously we've read a lot of the allegations that people are talking about," she said, referring partly to criticisms that some Diebold officials were too close to Republicans. "Obviously we cannot base our decision on hearsay or what's on the Internet."