故障现象:
Symptom:
接修了一台内窥镜冷光源。故障现象是:开机有电源指示,散热风扇工作正常,机内有连续的“哧哧哧”高压拉弧声,没有“啪、啪、啪”的放电声,氙灯没有工作,打开机器后发现放电管内好似烧焦发黑,再次开机放电管一直连续放电拉弧。
An endoscope cold light source was repaired. The fault phenomenon is: there is a power indicator when the machine is turned on, the cooling fan works normally, there is a continuous "Chi Chi" high-voltage arc sound in the machine, there is no "Pa, PA, Pa" discharge sound, and the xenon lamp does not work. After turning on the machine, it is found that the discharge tube is scorched and blackened. When the machine is turned on again, the discharge tube has been continuously discharging and arcing.
工作原理:
working principle:
氙灯的发光是利用正负电触发氙气与稀有金属起化学反应而发光的。根据气体放电的工作原理,对照电路分析氙灯弧光放电起辉原理:在氙灯工作的电路中并联有贮能电容,当电压直接加到氙灯两端电上,且充电电压小于灯的自闪电压时,氙灯不导电。
The luminescence of xenon lamp uses positive and negative electricity to trigger the chemical reaction between xenon and rare metals. According to the working principle of gas discharge, the starting principle of arc discharge of xenon lamp is analyzed by comparing with the circuit: there are energy storage capacitors in parallel in the circuit of xenon lamp. When the voltage is directly applied to both ends of xenon lamp and the charging voltage is less than the self flashing voltage of the lamp, the xenon lamp is not conductive.
电路辅助有高压触发电路,打开电源开关,变压器产生的高压使火花隙放电,产生的23000V左右的触发脉冲电压加到氙灯上,使氙灯电离,在灯内形成长火花,这个火花在灯两端电压上迅速成高密度的弧光放电,产生强的闪光,此时贮能电容上的电压通过氙灯放电以维持氙灯工作。当电容电压由于放电而下降到一定程度后,主电路加上,保持氙灯工作于弧光放电状态。
The circuit is assisted by a high-voltage trigger circuit. Turn on the power switch. The high voltage generated by the transformer discharges the spark gap. The generated trigger pulse voltage of about 23000V is added to the xenon lamp to ionize the xenon lamp and form a long spark in the lamp. The spark quickly forms a high-density arc discharge on the voltage at both ends of the lamp to produce a strong flash. At this time, the voltage on the energy storage capacitor is discharged through the xenon lamp to maintain the xenon lamp. When the capacitor voltage drops to a certain degree due to discharge, the main circuit is added to keep the xenon lamp working in the arc discharge state.
故障处理:
Troubleshooting:
由于听到了机内高压放电板上的“哧哧哧”的高压拉弧声,可以判定高压放电回路和氙灯均无故障。查主供电电源,放电拉弧时电压在110V左右,这说明贮能电容充放电正常,由于玻璃放电管内有烧焦发黑的现象,取下后解剖发现放电管内部电头有被氧化锈蚀,导致放电不切底不能激发氙灯工作形成连续拉弧。
As the "Chi Chi" high-voltage arc sound on the high-voltage discharge board inside the machine is heard, it can be determined that the high-voltage discharge circuit and xenon lamp are free of fault. Check the main power supply. The voltage is about 110V when discharging and arcing, which indicates that the charging and discharging of the energy storage capacitor is normal. Due to the phenomenon of burning and blackening in the glass discharge tube, it is found that the electric head inside the discharge tube is oxidized and rusted after being removed. As a result, the xenon lamp cannot be excited to form a continuous arcing without cutting the bottom of the discharge.
更换后开机,灯泡在啪的一声后点亮。测主电路供电板供电电压为18V,测3525集成的8脚0~4.8V、9脚,5V、10脚0V、11脚6.2V、14脚5V、16脚5.1V,输入、输出电压均正常,观察无异常,故障排除。
Turn on the machine after replacement, and the bulb will light up after a snap. Measure that the power supply voltage of the main circuit power supply board is 18V. Measure the 8-pin 0~4.8v, 9-pin, 5V, 10 pin 0V, 11 pin 6.2V, 14 pin 5V and 16 pin 5.1V of the 3525 integrated. The input and output voltages are normal. Observe that there is no abnormality for one day. The fault is eliminated.
内窥镜设备维修人员认为在光导纤维广泛应用的今天,医用冷光源在使用性能上发生了质的变化,为了在整体上让观察显示系统达到佳的视觉效果,氙灯光源逐渐替代了其他卤素灯光源。一般卤素灯与其相比,氙灯除了更省电外,还对设备的散热效果也有了大的改变。所以,要勤于“剖析”电路,掌握其电路原理,对以后的维修工作会有不少的帮助。
The maintenance personnel of endoscope equipment believe that with the wide application of optical fiber, the performance of medical cold light source has changed qualitatively. In order to achieve a good visual effect of the observation and display system as a whole, xenon light source has gradually replaced other halogen light sources. Compared with general halogen lamps, xenon lamps not only save more power, but also greatly change the heat dissipation effect of equipment. Therefore, we should be diligent in "analyzing" the circuit and mastering its circuit principle, which will be of great help to the future maintenance work.
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