The customer, a syncardia authorized distributor, reported that the freedom driver exhibited a fault alarm while supporting a patient.The customer also reported that the beat rate of the driver dropped from 142 beats per minute to 120 beats per minute during the fault alarm.The patient was subsequently switched to the backup freedom driver.There was no reported adverse patient impact.
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Visual inspection of the driver found metallic debris on the exhaust fan, exhaust fan cover, piston cylinder assembly (pca), motor-gearboxes and speaker printed circuit board assembly (pcba), and the secondary motor cam follower out of bottom dead center position (bdc).It was also observed that the primary motor dragged, wobbled, and made a loud grinding noise.Despite passing all functional test criteria, the driver exhibited a loud grinding noise upon operation.This grinding noise was likely caused by the primary motor cam follower hitting the scotch yoke dowel pin in the pca, rubbing against the inside wall of the pca resulting in the observed metallic debris.The customer-reported fault alarm and change in beat rate were confirmed and reproduced during investigation testing as they were the expected result of the engagement of the secondary motor as evidenced by the secondary motor cam follower being out of bdc position.The reason for the secondary motor engagement could not be determined conclusively, however, if the secondary motor cam follower moves sufficiently out of bdc such that it allows engagement with the scotch yoke, back-emf (electromagnetic field) from motion of the secondary motor will trigger the driver to disable the primary motor and engage the secondary motor.This issue will continue to be monitored and trended as part of the customer experience process.Syncardia has completed its evaluation and is closing this file.(b)(4) follow-up report 1.
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