故障现象 :球管无法升至最高位置 ( 150ｃｍ ) ,当需要在此高度进行摄片时 ,保护开关ＳＷ 2自动跳闸 ,无法工作。故障分析 :在机器中 ,影响球管升降的机械部分是受控制台所提供的电压经采样比较放大后 ,去驱动电机完成升降功能的。球管向下运动正常 ,向上运动不正常 ,估计是上 Failure phenomenon: The tube cannot be raised to the highest position (150cm). When it is necessary to take a picture at this height, the protection switch SW2 will automatically trip and fail to work. Fault Analysis: In the machine, the mechanical part that affects the rise and fall of the tube is amplified by sampling the voltage provided by the console to drive the motor to complete the lifting function. The downward movement of the tube is normal and the upward movement is abnormal. It is estimated that it is