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故障现象:图像极暗,亮度对比度置最大亦然,但伴音良好。分析检修:初步判断亮度通道异常。先测加速极电压为365V,基本正常。测N103(TA8690AN)(30)脚(对比度控制)电压为5.9V且可调,(34)脚(亮度控制)4V可调,说明CPU控制基本正常。测“-Y”信号放大器V201 b极电压为4.4V,e极为4.6V,也基本正常。为便于观察,人为调高加速极电压至420V左右,发现彩
Symptoms: the image is very dark, brightness contrast is set at the maximum, but good sound. Analysis and maintenance: a preliminary assessment of abnormal brightness channel. First test acceleration pole voltage of 365V, basically normal. Measured N103 (TA8690AN) (30) feet (contrast control) voltage of 5.9V and adjustable, (34) feet (brightness control) 4V adjustable, indicating CPU control is normal. Measured “-Y” signal amplifier V201 b pole voltage of 4.4V, e very 4.6V, also basically normal. To facilitate the observation, artificially increase the acceleration voltage to about 420V, found color