Medical linear accelerator is precisely large-scale medical equipment with high integration and complex construction.In use,it is easy to occur fault,and the maintenance process is tedious,and the cost of maintenance is higher.The servicers with medical engineering technique should proficiently know and grasp the structure and principle of this kind of equipment,and respond routine fault,and ensure the quality of accelerator in clinical application.This article analyzed a case of interlocking fault of stand power supply(STPS)of 23EX medical linear accelerator in the department of medical engineering of the Affiliated People's Hospital of Ningbo University.According to the performance of accelerator's fault,and combining the work principle of occurring STPS interlocking fault,the pulse width modulation(PWM)board in auxiliary electronic cabinet of accelerator was located.Its schematic diagram was analyzed and checked.Finally,it was determined that the reason was the field effect tube of PWM board was broken down.The fault was eliminated after the components of occurring fault was replaced.We can increase maintenance efficiency and technical level,and reduce the cost of maintenance for hospital,and ensure its quality in clinical application through quickly locate and resolve faults.

Medical linear accelerator is precisely large-scale medical equipment with high integration and complex construction.In use,it is easy to occur fault,and the maintenance process is tedious,and the cost of maintenance is higher.The servicers with medical engineering technique should proficiently know and grasp the structure and principle of this kind of equipment,and respond routine fault,and ensure the quality of accelerator in clinical application.This article analyzed a case of interlocking fault of stand power supply(STPS)of 23EX medical linear accelerator in the department of medical engineering of the Affiliated People's Hospital of Ningbo University.According to the performance of accelerator's fault,and combining the work principle of occurring STPS interlocking fault,the pulse width modulation(PWM)board in auxiliary electronic cabinet of accelerator was located.Its schematic diagram was analyzed and checked.Finally,it was determined that the reason was the field effect tube of PWM board was broken down.The fault was eliminated after the components of occurring fault was replaced.We can increase maintenance efficiency and technical level,and reduce the cost of maintenance for hospital,and ensure its quality in clinical application through quickly locate and resolve faults.