Ｓ 5 2 0型扫描电镜是一种应用广泛的大型精密仪器 ,高压保护性中断又是其常见故障之一 ,尤其是那些已使用了十几年、且已进入故障高发期的电镜设备 ,由于高压电路应用的特殊性 ,其故障的检测和排除比较困难。本文通过一高压中断故障 ,对总线数据输入接口、地址译码接口及透镜 S 5 2 0 scanning electron microscope is a widely used large-scale precision instruments, high-voltage protective interrupt is one of its common faults, especially those who have been using for more than a decade, and has entered the high incidence of failure of the electron microscope equipment, due to The particularity of the application of high-voltage circuit, the fault detection and troubleshooting more difficult. This article through a high-voltage interrupt fault, the bus data input interface, address decoding interface and lens