今天检修一台仿KR-500焊机,故障是打开焊机电源开关送丝机就送丝,焊机输出有11V的电压.
经检查发现,Q9B极不按枪开关就有0.74V工作电压,说明这个管已工作,另查QR9B极不按枪开关有2.4V工作电压.
另查QR4B极不按枪开关有0.05V工作电压,这说明光偶PC9不工作,PC8在工作.
请问各位高手,QR9的工作电压是怎样建立起来的?
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