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[例1]故障现象 开机时只有“吱”一声后无任何反应,无光栅无伴音;此时关机有“呜”声。 分析与检修 从现象分析可知,机内直流电源应正常,可能是行扫描电路故障。开机检修未发现四路直流有明显短路故障,用假负载通电检测电源,发现B4(26V)无输出,其它电压正常。关机后通过检测发现保险电阻R371已开路并有烧焦迹象,这说明此路负载有电流过大情况。此电压分三路输出:一路是送到IC201,检测该路保险电阻R401正常,此路故障可能性不大;第二路是送至行激励,检测有关器件均正常;第三
[Example 1] Symptom There is no response when there is a “squeak” at boot, there is no sound without grating; Analysis and Maintenance From the phenomenon analysis shows that the DC power inside the machine should be normal, may be line scan circuit failure. No significant short-circuit fault was found in the four-channel DC power-on maintenance. The power supply was powered by a dummy load to detect the power supply, and no output was found at B4 (26V). Other voltages were normal. After shutdown by testing found that the insurance resistance R371 has been open and signs of burning, indicating that this road load current is too large. This voltage is divided into three outputs: all the way to the IC201, testing the road insurance resistor R401 normal, this road is unlikely to fault; the second road is to send to the line incentives to detect the devices are normal; third