故障现象：接通电源，预热三分钟，低压指示灯亮而高压指示灯未亮，调节输出旋钮，电流表无指示，病人无热感，用试验指示灯管于发射器处，灯管不亮。分析与检修：从故障现象来看，磁控管没有工作，测得磁控管灯丝两端电压为零，因此怀疑供电系统存在问题。该机为使磁控管不受 Symptoms: Turn on the power, warm up for three minutes, the low pressure indicator light and the high pressure indicator is not lit, adjust the output knob, no indication of the ammeter, the patient has no thermal sensation, use the test indicator tube at the transmitter, the lamp is off. Analysis and Maintenance: From the point of view of the fault phenomenon, the magnetron did not work, and the voltage across the magnetron filament was measured to be zero. Therefore, it was suspected that there was a problem with the power supply system. The machine is not subject to magnetron