Towns across Southern New Hampshire will test their voting machines in coming days in preparation for primary voting Sept. 9.

Several local towns have had problems with voting machines in the past, but there is more concern about human error, officials said.

Blank ballots, over-votes (when too many selections are made on a ballot) and write-ins all can be subject to human error. Those ballots will be examined carefully by town officials to be sure they are counted properly, according to Windham Town Clerk Joan Tuck.

"We have to make sure they are counted the way they appear to us," Tuck said.

In March, Windham had problems with its voting machines when the ballots for Town Meeting elections were sent through in test mode. The ballots ultimately were recounted properly and results from the election eventually were posted, Tuck said.

Salem also had troubles with its voting tallies at Town Meeting when compiling votes from six voting machines. The results from the election were printed off the machines and added up on a computer, but that computer had a faulty keyboard, which repeatedly recorded the number 6 into the data. As in Windham, the problem in Salem was not related to the machines counting ballots. The ballots were eventually successfully processed.

Voting machines record ballots with properly filled ovals and sorts out blanks, over-votes and write-ins, which are checked by officials and the votes recorded.

The state requires machines to be tested publicly within one week of elections and the testing results must be sent to the secretary of state. Many towns, including Salem and Pelham, will test their machines tomorrow.

Pelham switched from one kind of machine to another three years ago, but has never had a problem with either during testing. It takes the town about an hour to test its one machine, Town Clerk Dottie Marsden said. The new system is easier to use and test, but neither system has ever had a problem during testing, Marsden said.

Sandown typically tests its machine with 50 ballots and has never had any problems, according to Town Clerk Michelle Short.

Machines are tested by processing ballots of the possible voting scenarios through the machine and also hand count of all the ballots. Then the results are compared to make sure the machine tallies are correct.

Primary elections will be held on Sept. 9. The last day for new voters to register before the election is Sept. 2, but voters can also register at the polls the day of the election.

It's not too late to register

The last day for new voters to register before the election is Sept. 2. Voters can also register at the town clerk's office on or before Sept. 2. Registration also is available at the polls on Sept. 9.

Here are the times and places for new voter registration Sept. 2.

Town%Where%When

Atkinson%Atkinson Community Center%7 to 7:30 p.m.

Derry%Town Clerk's Office%7 to 7:30 p.m.

Hampstead%Town Office Building%7 to 7:30 p.m.

Kingston%Town Hall%7 to 7:30 p.m.

Londonderry%Town Clerk's Office%6 to 7:30 p.m.

Newton%Town Hall%7 to 7:30 p.m.

Pelham%Police Meeting Room%7 to 7:30 p.m.

Plaistow%Town Clerk's Office%7 to 7:30 p.m.

Salem%Municipal Office Building%7 to 8 p.m.

Sandown%Town Hall%7 to 7:30 p.m.

Windham%Town Clerk's Office%7 to 9 p.m.