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故障现象:开机,LED指示灯不亮,整机无任何反应。分析与检修:从故障现象可知,该机开关电源电路有故障。DVD视盘机由于用电电压低、电流小,检修开关电源时无需接假负载。于是,打开机盖,卸下电源板查看,首先发现启动电阻R807(330kΩ)断路。更新后,通电测量T802开关变压器初级侧C805两端电压为335V,正常;Q802(A6351)、Q821(P621)也完好;然后检查T802次级侧插拔件CN801各绕组(电压输出端)电压均为0V,不正常。
Symptom: boot, LED light does not shine, the whole without any reaction. Analysis and Maintenance: From the phenomenon of failure we can see that the aircraft switching power supply circuit failure. DVD player due to the low voltage, current, overhaul switching power supply without taking the dummy load. So, open the cover, remove the power board to see, first find the start-up resistor R807 (330kΩ) open circuit. After the update, the voltage across the primary side of the T802 switching transformer, C805, is measured at 335V, and Q802 (A6351) and Q821 (P621) are also good. Then check the voltage at each winding (voltage output) of T802 secondary side plug CN801 0V, not normal.