故障表现为:无背光 维修与分析:测电源板各组输出电压正常,分析背光不亮故障应该在背光板上,测量24V和开机电平;亮度电压和背光开关信号均正常。仔细测量Q649的B极电压0.7V正常,Q650的B极电压16.5V,E极24V正常,但C极无电压,Q650是PNP管。试更换Q650后试机图声正常。 |
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