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故障现象:显示的文字模糊不清,细看字迹的横竖划有严重漏点现象.分析检修:显示器能显示说明显示器的行、场扫描电路及高压发生器电路均工作正常.显示器显示的字迹不清,字的横竖划有漏点现象,判断故障部位出在视频放大电路内,可能是视频信号弱所致.首先用示波器测视放管Q1集电极视频信号幅度为25VP-P,用电压表测Q1集电极电压为42V,说明视放管Q1集电极输出视频调辉信号正常应不低于40VP-P左右.结果表明:确因加到显象管阴极的视频调辉信号弱而使字的横竖划有些光点显示不出来,造成字迹模糊不清.用示波器测试电主机送到显示器输入端的视频信号为1VP-P正常,视频信号经集成块
Symptoms: the display of text blurred, look at the handwriting of the horizontal and vertical draw a serious leakage phenomenon Analysis and maintenance: the monitor can display the display line, field scan circuit and high voltage generator circuit are working properly. Clear, the word is marked with leakage phenomenon, to determine the fault part of the video amplifier circuit, the video signal may be caused by weak first oscilloscope measurement of the collector Q1 video signal amplitude of 25VP-P, with a voltmeter Measured Q1 collector voltage is 42V, indicating that the tube collector Q1 output video tonal signal normal should not be less than about 40VP-P. The results show that: indeed added to the negative pole of the cathode ray image brightness signal weak and the word The horizontal and vertical points of some of the dots can not be displayed, resulting in illegible handwriting with the oscilloscope test the host computer to the video input signal is 1VP-P normal video signal through the manifold