500 mA medical-x-ray machine is widely appliced in national hospital. This equipment structure is beautiful and the performance is reliable, but this machine circuit is complicated and it is easy to appear faults.

First, Fault phenomena

 if you choose fluoroscopy, the camera work normally. The tube of under diagnosis bed cann’t exposure when exposure spot film. Then you can choose spot film pulley of 1 points case, two points case, four points case, it work normally.

 Second, Fault reason processing

Fault was appeared in spot film switch control circuit: You can check spot film control circuit and open the machine to test; Then press spot button, spot film pulley turn left to run. Perspective spot film of spot film pulley transfer switch; After that, connect CZ9-11 with CZ9-12, you can hear the voice of rotating anode of under bed tube, spot film pulley come back original position; Then, relay JC2 start to work and rotating anode start running ,J10, protective relay begain to work. JC3, which is on top of high pressure, begain to exposure. You can open the console to observe and you will find that the relay of high pressure top, JC3 don’t work. The relay of JC3 is controled by J10 and you can observe J10 and it doesn’t work. J10 is delaing relay of starting protection. In starting protection delay relay circuit, B5 is transformer of filament heating; B6 and B7 are starting transformer of rotating anode; B5, B6 and B7 can induce 10v voltage. BG41, BG43 and BG44 are consist of J10. Because rotation start normally, so B6 and B7 have induced voltage. But B5 has no induced voltage, B5 induced voltage is from tube filament heating loop and it proves that there is open circuit in filament loop. Take down high-pressure primary P1, P2 and check high voltage generator and find that filament heating primary loop has voltage output. Pull out high voltage generator cathode cable and test that there is filament voltage; Then measure tube filament resistance and find it normal; At last, you can test high voltage cables big focus on both ends and small focus fluoroscopy is normal, then you can replace cable head, JC2, J10, JC3 work and test high pressure primary P1, P2 and find that there is voltage on it. Connect P1 with P2 and open the machine, mA display normally.

Third, Conclusion

You must repair it in accordance with inspection maintenance program. The maintenance program is very clear and don’t cause new fault. In fact, be familiar with the circuit principle is the most important.

本文由广州佳誉医疗器械有限公司编辑