Ｆ78--Ⅲ型300ｍＡＸ线机是双床球管固定式Ｘ线机,可进行透视、摄影、胃肠诊断等工作,适宜于中型以上的综合医院使用。但该机的刹车电路设计不太合理,很容易导致出现一些故障,稍不注意就会烧毁元件。故障现象:隔离变压器烧坏。原因分析:从电路图可知,隔离变压器Ｂ20次级电压供 The F78--III type 300mA X-ray machine is a twin-tube fixed X-ray machine, which can perform perspective, photography, gastrointestinal diagnosis and other work, and is suitable for use in general hospitals above medium-sized ones. However, the design of the brake circuit of the aircraft is not reasonable, it is easy to cause some failures, and it will burn the components with little attention. Fault phenomenon: isolation transformer burned out. Analysis of the reason: From the circuit diagram, it can be seen that the secondary voltage of the isolation transformer B20 is