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Additional information: section h8: reuse.Device evaluation: sections h3, h6, h7, h10: the reported problem was reviewed by a team of siemens product experts and assessed by quality and regulatory specialists.On (b)(6) 2022, an x-ray was not possible on plane b of a biplane system during an interventional procedure.The generic error message "no xray, tube too hot" was displayed for plane b.Plane a was working without limitation.Therefore, the procedure could have been stopped in a controlled manner if needed.However, the customer rebooted the system (according to the general recovery procedure described in the operator manual), which resolved the present failure, and the procedure was continued on the imperfect system.Thereafter the siemens service was called for failure investigation.The detailed investigation revealed that the cause of the blocked x-ray release was a temporary problem in the internal signal processing.In regular intervals the hardware is checked automatically.Within this check the signal line between relevant sensors and the evaluation component is tested.The test is triggered when a relay switches the contact to the sensors off and back on.The d1-board (evaluation component) detects the falling edge and checks that the voltage drops below a defined "low" level and remains like that for a defined, short period of time.In the present case, it was found that the contact of the relay showed bounce effects/voltage fluctuations.This triggered multiple, successive falling edges that repeated the cable test.However, since the voltage must remain in the "low" state for a certain time for the test to pass, this caused the test to fail even though there was no fault on the signal line.As a result, the x-ray release was prevented for plane b to avoid possible severe damage to the x-ray tube.Normal operation of the system was restored by a "power cycle," i.E., the system was shut down and turned back on so that the associated components (x-ray generator, tube) were restored to normal.To permanently resolve the problem, the d1-board was exchanged as part of service activity.The error mentioned in the complaint has not again been reported since then.Further it is planned to release a field-update to this sporadic problem by the end of september 2022.The incident described was not classified as a reportable adverse event after detailed investigation, because neither serious injury, death nor an unexpected, prolonged hospitalization of the patient or any other person occurred or could be expected.The corresponding probability according to the risk analysis is in the range of inconceivable.
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