打开机壳,STV8172a各脚电压1-1.2伏,2-14伏,3-负14伏,4-负14伏,5-0.1,6-14伏,7-1.0左右。电压基本正常!代换STV8172a,无效。查OM8373PS芯片,14脚8伏正常,21场激励,0.9伏,场锯齿波0.9正常。代换STV9302场块5脚输出端接的阻尼电容C303(220N,63伏),换升压二极管,换升压电容50伏,100uf,无用。查场块外围的电阻,电容无果。检修至此陷入,最后测电感L401电阻180欧实际不能大于1欧用0.33欧电阻代替一切正常 |
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