A bad Breathalyzer machine in the basement of the Philadelphia Police Department has caused more than 400 drunken-driving cases to skid into limbo.

The machine, one of a handful the department uses to obtain the blood-alcohol content of people arrested on suspicion of drunken driving, was not properly calibrated from Nov. 27 through late February, Lt. Ray Evers, a department spokesman, said yesterday.

The department, on Feb. 25, notified the District Attorney's Office that 416 arrests were affected, said Evers, who added that the defective machine is no longer in use.

Defense attorneys have been notified that if their clients have already pleaded guilty or been found guilty, they can request new trials. If their trials are pending, data from the faulty machine will not be used in court, said Tasha Jamerson, spokeswoman for the D.A.

There are no plans, however, to dismiss any cases, Jamerson said.

"We've not thrown out any, because there is evidence other than the Breathalyzer," she said, noting that testimony from eyewitnesses and results from blood tests can also be used to prosecute suspected drunken drivers.

A Breathalyzer test "is the last step in a DUI arrest. It's one portion," Evers said. Also important, he said, is an officer's observation of a motorist's speech, gait, eyes and performance on a field-sobriety test.

Jamerson said it is too early to know how many defense attorneys will ask for new trials because they were notified only a week and a half ago.