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机型;长虹C2939KS型“画中画”彩电。故障1 开机三无。按常规检查电源电路和行扫电路元器件未发现异常,通电测得主电压+115V为0V,而C_(809)(560μF/450V)两端的300V电压正常。再次仔细检测,均未发现问题,维修陷入困境,只好用替换法来查找故障件。先对阻容元件进行替换,但故障依旧。再对光电耦合器及二、三极管进行替换,故障仍
Model; Changhong C2939KS type “picture in picture” color TV. Fault 1 boot three no. According to the routine examination of the power circuit and the line scan circuit components found no abnormality, the main voltage + 115V is 0V, while the C_ (809) (560μF / 450V) at both ends of the 300V voltage is normal. Again carefully tested, did not find the problem, maintenance troubled, had to use replacement method to find the fault. The first RC element replacement, but the fault still. Then optocoupler and two, transistor replacement, the fault is still