论文部分内容阅读
故障现象:彩电启动困难,但如果一旦启动后,彩电可以一直工作下去;而不能启动时,彩电面板指示灯一闪即灭,同时机内发出“吱”的一声,彩电处于保护状态。分析检修:根据故障现象可以判断,这是一例“软故障”,多数为该机保护电路本身出了问题。因为假如保护电路后级有故障,通常情况下不会总是在开机的瞬间发生保护,更不可能在启动后能够一直工作下去。当故障出现时,用万用表测量主电压为0V,而可控硅Q902的控制极电压为0.6V,证明电路确实已经处于保护状态。该机保护电路如图1所示。由于该保护
Symptom: Color TV start-up difficulties, but if once started, the color TV can always work; and can not start, the TV panel flashing light is off, while the machine issued a “squeak”, the TV is protected. Analysis and maintenance: According to the phenomenon of failure can be judged, this is an example of “soft fault”, the majority of the aircraft protection circuit itself has a problem. Because if the protection circuit after the fault, usually under the protection of the moment will not always occur, but can not continue to work after starting. When the fault occurs, the main voltage is measured with a multimeter 0V, and the controllable voltage of the silicon controlled rectifier Q902 is 0.6V, to prove that the circuit is indeed in a protected state. The machine protection circuit shown in Figure 1. Due to the protection