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一台SR-531F型卫星电视接收机,因遭雷击,开机通电后,电源指示灯发光正常,但高频头指示灯不发光,无视频、音频信号输出。检修:打开机壳,首先用万用表测高频头指示灯两端电压为零,后测第二变频器LNB无19V电压,用Ω档测R_(836),发现此电阻呈开路状态,因此电阻是保险电阻,但不能直接短路,而手头又无此电阻,为应急用一只5×20的0.5A-0.75A的熔丝保险管代用,具体作法是把原电阻焊下,把保险管焊在原电阻处即可。换上后,接通电源时高频头的指示灯还是不发光,证明机内还有损坏的元件:当检查到D_(812)稳
An SR-531F satellite TV receiver, due to lightning, power on the power indicator light is normal, but the high-frequency head light does not light, no video, audio signal output. Overhaul: Open the case, first with a multimeter head tuner voltage across the zero, after measuring the second inverter LNB no 19V voltage, Ω file with R_ (836) and found that the resistance was open, so the resistance Is the insurance resistance, but can not be directly short-circuited, but no such resistance on hand, for emergency use a 5 × 20 0.5A-0.75A fuses fuse substitution, the specific approach is to the original resistance welding, the fuse At the original resistance can be. Put on, the power of the tuner when the light is turned on or not light, there is evidence of damage to the machine components: When the check to D_ (812) steady