故障现象：开机后用５ｍｍ设置扫描正常，但转换到１０ｍｍ层厚作扫描准备时，机器很长时间不能完成准备且自动废止，文本显示器上报出“准直器２．５分后仍在移动”。分析检修：打开机架前盖板，观察准直器运动情况，正常时上准直器是根据设置接孔径、层厚、滤过的顺序工作，? Symptom: After starting the machine, the scanner is set to scan normally with 5mm, but when it is switched to the 10mm layer for scanning preparation, the machine will not be able to complete the preparation for a long time and will be automatically retired. The text display shows that “the collimator is still moving after 2.5 minutes.” . Analysis and maintenance: Open the front cover of the rack and observe the movement of the collimator. In normal operation, the upper collimator works according to the order of the installation aperture, layer thickness, and filtration.