故障现象:无图像、无伴音、无字符,屏幕中间有亮带,左右两边有两条暗带。故障分析:屏幕中间亮,左右暗,是行扫描电路工作异常的表现;无图像、无伴音、无字符是CPU没有进入工作状态的表现,而有些CPU只有得到正常行、场逆程脉冲才能进入工作状态。所以,本机应先检查两类故障共同涉及的行扫描电路。 Symptoms: no images, no sound, no characters, bright band in the middle of the screen, left and right sides have two dark bands. Fault analysis: the middle of the screen bright, left and right dark, is the abnormal performance of the line scan circuit; no image, no sound, no character is the CPU did not enter the working state of performance, and some CPU only get normal line, field pulse can enter Working condition Therefore, this machine should first check the two types of faults commonly involved in the line scan circuit.