1.切断联动保护电路,确定故障范围进入待机状态时,将行失压检测电路的Q1123的基极与地短路,切断行失压保护的触发电压,使开/关机电路保持开机状态。短路Q1123后,短路行输出管Q601的基极与发射极,切断行推动信号,接假负载进行开机试验,并测量开关电源的输出电压。如果开机后,继电器RYl70l仍不吸合,故障在微处理器和开关机电路;如果继电器RYl701已吸合,但开关电源无电压输出,故障在开关电源电 1. Cut off the linkage protection circuit to determine the fault range into the standby state, will line loss detection circuit Q1123 base and ground short circuit, cut off line voltage protection trigger voltage, so that the on / off circuit to maintain the power on state. Short circuit Q1123, the short circuit line output tube Q601 base and emitter, cut off the line to push the signal, then leave the load for the boot test, and measure the output voltage of the switching power supply. If the boot, the relay RYl70l still does not pull the fault in the microprocessor and the power switch circuit; if the relay RYl701 has been sucked, but the switch power supply voltage output failure in the switching power supply