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1.观察故障现象(1)烧保险丝F801烧保险丝说明电源有严重短路性故障,先检查开关管Q801是否击穿。当Q80l击穿后,一般还伴随着Q802、Q803、D804也击穿。击穿的原因可能是交流电网电压过高或稳压电路失控,如IC801、D809开路。若开关管Q80l没有击穿,则烧保险丝的原因多数是整流二极管D801击穿或滤波电容C801、C802、C807击穿。可用电阻测量方法对开关电源主要三极管进行测量,该机芯开关电源三极管的对地电压,参见表1所示。
1. Observe the phenomenon of failure (1) burning fuse F801 burning fuse Description power serious short-circuit fault, the first check switch Q801 breakdown. When the Q80l breakdown, the general also accompanied by Q802, Q803, D804 also breakdown. Breakdown may be due to the AC grid voltage is too high or the regulator circuit out of control, such as IC801, D809 open. If the switch Q80l no breakdown, then the majority of burning fuse reason is the breakdown of the rectifier diode D801 or filter capacitor C801, C802, C807 breakdown. Available resistance measurement method of switching power supply main transistor for measurement, the movement of the power transistor transistor to ground voltage, see Table 1 below.