最新液晶电视黑屏的维修方法.doc

液晶电视黑屏的维修方法
actively carry out the law on civil air defense education, drawn out of the air defense in Pinglianrdize internal management, improve staff quality. Adhere to the
actively carry out the law on civil air defense education, drawn out of the air defense in Pingliang city Building under easy fare, daily special inspection and regulation, overfulfilled the province upper and lower knots of up to 500,000 yuan fee collection tasks. 5, further standardize internal management, improve staff quality. Adhere to the
7、高频信号处理板
8、外壳
引起黑屏问题有多种原因：
首先是电源电路不正常引起：表现为按面板按键无任何反响，指示灯不亮，
先查12V电压正常否，跟着查5V电压正常否，因为A/D驱动板的信号处理局部的芯片的工作电压都是5V，所以查找开不了机的故障时,先用万用表测量5V电压，如果没有5V电压或者5V电压变得很低，那么一种可能是电源电路输入级出现了问题，也就是说12V转换到5V的电源局部出了问题，这种故障很常见，一般是烧保险或者是稳压芯片出现故障，有局部机器是把开关电源内置，输出两组电源，其中一组是5V，供信号处理用，另外一组是12V提供高压板点背光用，如果开关电源局部电路出现了故障会有可能导致两组电源均没输出。另一种可能就是5V的负载加重了，把5V电压拉得很低，换一种说法就是说，后级的信号处理电路出了问题，有局部电路损坏，引起负载加重，把5V电压拉得很低，逐一排查后级出现问题的元件，替换掉出现故障的元件后，5V能恢复正常，故障一般就此解决，也经常遇到5V电压恢复正常后还不能正常开机的，这种情况也有多种原因，一方面是MCU的程序被冲掉可能会导致不开机，还有就是MCU本身损坏，比方说MCU的I/O口损坏，使MCU扫描不了按键，遇到这种由MCU引起的故障，找硬件的问题是没有用的，就算你换了MCU也解决不了问题，因为MCU是需要编程和写玛的，在没方法找到原厂的AD驱动板替换的情况下，我们只能另寻途径找可以代换的A/D驱动板，市场上有好多地方都可以购置到，如果当地市场购置不到的话，可以在液晶之家论坛上发帖看看，论坛上面有很多液晶方面的高手，或许可以购置到你需要的配件及找到你需要的资料。
actively carry out the law on civil air defense education, drawn out of the air defense in Pingliang city Building under easy fare, daily special inspection and regulation, overfulfilled the province upper and lower knots of up to 500,000 yuan fee collection tasks. 5, further standardize internal management, improve staff quality. Adhere to the
actively carry out the law on civil air defense education, drawn out of the air defense in Pingliang city Building under easy fare, daily special inspection and regulation, overfulfilled the province upper and lower knots of up to 500,000 yuan fee collection tasks. 5, further standardize internal management, improve staff quality. Adhere to the
actively carry out the law on civil air defense education,