If you want to maintain medical-x-ray machine, you must be familiar with drawing and know about work principle. The most important is that you must learn about using some inspection methods because it can help you to find the fault quickly and accuratly. In many years, using the way of measuring devices voltage, you can solve many problems. Now, make the example of eliminating XG200 x-ray machine failure:

First failure

Fault phenomena: Press PA, SC, it cann’t work and the x-ray tube doesn’t exposure.

Examination: It works normally after rotating anode, YJ close. Using multimeter measure input terminal 107, 234 voltage of Is chronotron XSJ. If there is voltage, it proves that chronotron can work normally. Inspecting output voltage of 236, 266, 1s ralay can work in general conditions and usual open contacts closed. Terminal voltage should be zero. But examinate it, it has voltage. It proves that contacts are not closed and you can judge the relay has problems. After taking it down, you can find that 12V voltage tube breakdown. After exchanging stabilivolt, you can remove failure and the machine work normally.

 Second fault

 Fault phenomena: No exposuring

Inspection: Delay relay can work normally. Timer JSB input the line 101, 210 have voltage. If the timer has power, it can work normally. But measure timer JSB output contacts 102, 202 having voltage, it expresses that JSB1 doesn't closed and judge timer has problems. Taking it down, you can find that drive relay middle power tube C pole demage and lead to relay cann't work. After maintaining, the machine can work normally.

Third failure

Fault phenomena: It is the same with no exposuring.

Inspection: It works normally after rotating anode and 1s relay work usually. Measure timer output contacts JSB1, 102, 202 voltage. If it exposures, there is no voltage, SC cann't work. Then check SC contacts (GBJ1)202, 254 voltage. If there is voltage, it proves that timer works normally. The fault is in protection circuit. Take down overload circuit board to examinate and find that small relay GBJ touch bad contacts. After repairing it, it can work again.

Fourth Failure

Fault phenomena: Medical-x-ray machine exposure excessivly and film is black.

 Inspection: When you measure the machine, you find that no matter timer is in any grade, exposuring timer SC should absorb a long time to release. Contactor iron core surface has dirt or rust and will delay release after no power. Exactly timer has problem or contactor, you can use multimeter to measure SC coil two ends work voltage and adjust timer in 0.5s grade, then press PA, voltage disappear in regulation time, but SC is still closed and release after a long time. Using the other time grade is the same with that. So you can judge timer no problem and contactor has problem.

In usual repairing process, although it meets different faults, you can use knowledge you learned and use some reliable measuring methods by analysis and remove failure quickly.

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