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“三无”故障是康佳 T2979DI 型机的常见病。导致“三无”故障的原因一般在于电源部分和行扫描输出级工作不正常,但还可能由其他部分引起,因此必须对电路进行认真分析,细心检测才能找到具体原因。本机遥控电源(+5V)和主电源+B(130V)共用一个开关变压器,所以,只要电源指示灯亮,应该说明开关电源已经工作,本机电源输出过载保护电路特点是:该过载执行器件可控硅导通,切断行振荡电流,使行输出级停止工作,但开关电源仍能正常输出。所以,电源指示灯亮时出现“三无”故障,就要在行扫描、场扫描、待机控制电路、过流、过压保护电路等找原因;而在电源指示灯不亮或暗亮时出现故障,应查开关电源本身。
“Three no ” failure is a common disease Konka T2979DI type machine. The cause of the “3 None” fault usually lies in the abnormal working of the power supply and the line scan output, but may also be caused by other parts. Therefore, the circuit must be carefully analyzed and careful detection can be carried out to find the specific reason. The local remote control power supply (+5 V) and the main power + B (130V) share a switching transformer, so long as the power indicator light, should indicate that the switching power supply has been working, the power output overload protection circuit features: The overload actuator Silicon controlled conduction, cut off the line oscillating current, the output stage of the line to stop working, but the switching power supply can still be normal output. Therefore, the power indicator light “” “three no ” failure, it is necessary in the line scan, field scan, standby control circuit, overcurrent, overvoltage protection circuit to find the reason; the power light is not lit or dark Failure, should check the power switch itself.