论文部分内容阅读
故障现象:一台海信2117型彩电,上门维修,发现待机指示灯能由明转暗,但不能开机。分析与检修:根据理论,当机器“三无”时,首先检查电源输出130V,正常,测“行管”集电极130V 也正常,基极是负压,再向前查,激励级三极管集电极电压明显升高(正常为18V 左右),再测基极电压为0V,证明故障为无行频脉冲输出,故障范围在μPC1423CA 块及外围元件。首先测供电(14)、(38)脚,正常,再仔细测试行脉冲信号有关脚,无异常,用放大镜观看也没有明显
Symptoms: a Hisense 2117 color TV, home repair, found that the standby light can be bright to dark, but can not boot. Analysis and Maintenance: According to theory, when the machine “three noes”, first check the power output of 130V, normal, measured “in charge of” 130V collector is also normal, the base is negative pressure, and then look forward, the excitation level transistor collector The voltage is obviously increased (normal is about 18V), and the base voltage is measured again to 0V, which proves that the fault is no line frequency pulse output, the fault range is in the μPC1423CA block and peripheral components. First test the power supply (14), (38) feet, normal, and then carefully test the line pulse signal on the foot, no abnormalities, no significant with a magnifying glass