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故障现象 开机后,当选择导联前进或后退开关时不起作用,导联选择指示亮灯位置不变。分析检修 根据上述故障现象,初步判定导联选择计数器ＩＣ212无正常编码输出。原因有三(1)ＩＣ212本身发生故障,不能进行正常的加减计数;(2)ＩＣ212的第15脚没有计数时钟脉冲输入,即导联选择按
Symptom After power on, it does not work when the lead forward or back switch is selected. The lead selection indicator light position does not change. Analysis and maintenance According to the above-mentioned fault phenomenon, it is initially determined that the lead selection counter IC212 has no normal code output. There are three reasons: (1) The IC212 itself is faulty and cannot be counted up or down normally; (2) The 15th pin of the IC212 does not count the clock pulse input, that is, the lead selection is pressed.