一、电源与保护电路维修技巧该机的开关电源初级以厚膜电路STR—F6629为核心的过压、过流、过热保护电路启动时,迫使开关电源停止工作,开关电源输出电压降到0,产生自动关机现象,引发“三无”故障;以晶闸管SR802为核心的保护电路启动时,迫使开关电源工作于窄脉冲状态,开关电源输出电压降低,负载电路停止工作,也会产生自动关机现象,引发“三无”故障;以晶闸管RS803为核心的保护电路启动时,切断会聚电路的供电,会产生会聚不良 First, the power and protection circuit repair skills The machine’s primary switching power supply thick film circuit STR-F6629 as the core of over-voltage, over-current, over-temperature protection circuit starts, forcing the switching power supply to stop working, the switching power supply output voltage dropped to 0, When the protection circuit with thyristor SR802 as the core starts up, the switching power supply is forced to work in a narrow pulse state, the output voltage of the switching power supply is reduced, the load circuit stops working, and an automatic shutdown occurs Phenomenon, trigger “three no ” fault; thyristor RS803 as the core of the protection circuit starts, cut off the convergence circuit power supply, there will be convergence failure