论文部分内容阅读
故障现象:开机后有伴音和光栅但有回扫线,几秒钟后光栅自动消失,消失后机器有“吱吱”声,连续开机不再启动,但过一会再开机又重复上述故障。故障检修与分析:彩电无光栅故障有三个方面的原因:①保护电路起作用;②行电路本身出现故障;③视放电路出现故障造成显象管处于截止状态。此故障看来属第一种原因。该机过电压、过电流保护电路见图1。断开R_(754)(5.6k),测行管2SD869的集电极电压V_c=110V,这时光栅特别亮,亮度和对比度
Symptom: After the boot with sound and raster but there are retrace lines, a few seconds after the grating disappears automatically, the machine disappears, “creak” sound, continuous boot no longer start, but after a while then boot and repeat the fault. Troubleshooting and Analysis: There are three reasons for failure of the color grating TV: ① The protection circuit works; ② The circuit itself is faulty; ③ The circuit is in the turn-off state due to the fault of the display circuit. This failure seems to be the first reason. The machine over-voltage, over-current protection circuit shown in Figure 1. Disconnect R_ (754) (5.6k), the collector voltage V_c = 110V of the measuring tube 2SD869, then the grating is particularly bright, brightness and contrast