论文部分内容阅读
2 因接触不良而引发的自动关机故障接触不良使电路连接点的接触电阻增大,甚至造成开路现象,从而改变了功能电路的参数,或者改变单元电路结构,导致彩电自动关机。造成接触不良的原因很多,其中虚焊所占的比例最高。印制电路板的机械化波峰焊接,使某些元件的焊点吃锡很少,为虚焊埋下了隐患。如某些大功率元件(如电源开关管、行输出管或大功率电阻等)的引脚长期反复的热胀冷缩过程加速了引脚与印制电路板之间虚焊的形成。彩电中为数不少的接插件的表面产生氧化层,开关的接点或电位器内弹簧片氧化锈蚀则是造成接触不良的另一个重要原因。而某些印制电路线过细而又长期受到应力作用或者环境污染而腐蚀等原因也会产生断裂现象。由接触不良引发的彩电故障现象是多种多样的,请看下面六个实例。
2 due to poor contact caused by automatic shutdown failure Poor contact makes the circuit connection point contact resistance increases, or even cause an open circuit, thus changing the function of the circuit parameters, or change the unit circuit structure, resulting in automatic shutdown color TV. There are many reasons for poor contact, of which the highest share of Weld. Printed circuit board mechanized wave soldering, so that some of the solder joints to eat tin is very small, laid the hidden dangers Xu Jun. Such as the high-power components (such as power switch, line output tube or high-power resistors, etc.) pin long-term repeated thermal expansion and contraction process to speed up the pin and the printed circuit board Weld between the formation. Color TV in a large number of connectors on the surface of the oxide layer, the switch contacts or potentiometer within the spring oxidation corrosion is another cause of poor contact another important reason. And some printed circuit line is too thin and long-term stress or corrosion and other environmental causes can also cause rupture. Color TV failure caused by poor contact is a wide range of phenomena, see the following six examples.