检修过程:用万用表测显像管视放矩阵三个三极管基级电压是1.2V偏低,三个阴级电压是180V偏高,故判断视放集成电路TDA3504 故障,断开三基色输出端测还是偏低,买一个块换上故障依旧。后来调高加速级电压,出现一条 水平亮线,故判断场块坏了,换了场块,出乎意料一切都好了. 结论:TDA机芯场块坏引起黑屏,故应加大加速级电压判断才能不走弯路! |
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