(b)(4).On (b)(6) 2013, the customer, reported that at the end of a patient ct clinical procedure, the operator was moving the couch out of the gantry and down.When they released the button the couch went back in towards the gantry about eight inches.Upon further investigation, the customer indicated this has happened three times in the last month.The dates of the other occurrences are unknown.This record will be for the second occurrence, two subsequent complaints have been submitted for the other two occurrences.In this case, the customer reported that at the end of a patient ct clinical procedure, the operator was moving the couch out of the gantry and down.When they released the button the couch went back in towards the gantry about eight inches.There was no report of harm to a patient or operator.The customer contacted philips help desk to inform them of the issue and an fse was dispatched to the site.On (b)(6) 2013, the fse arrived on site and evaluated the system.Upon evaluation, the fse was unable to duplicate the problem.The couch and support operation was tested with the controls and the horizontal calibration was performed with no problems on the same day as the problem occurred.On (b)(6) 2013, the following parts were replaced: the safety cable, cable harness adapter, cable harness table plate, potentiometer lead.The fse thought w716 could be the problem.He also had swapped out two cables which had the same pin out.The fse determined that the issue occurred due to a failed cable in the couch control circuit.The parts were provided for engineering assessment.No log files were available.Engineering investigation of the defective parts, concluded that the replaced cable had a loose connector pin.Engineering determined the most probable cause of the issue was a failed cable in the couch control circuit.Ct engineering determined that the risk for this event was acceptable and, the mitigations for this issue include: vertical motion locked by additional brake when power is off.Two, redundant monitors are controlling the motion.A collision calculation is done in each combination of vertical, horizontal, or tilt motion.Hw emergency stop button stops all the motions.Buttons test during initialization.When the couch has the 'bedrock' configuration, the geared motor shall hold the couch at maximum load when the motor brake is not functional or removed.
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