故障现象:开机时图像散焦,逐渐变清晰。分析与检修:此为常见故障,可断定显像管管座问题,需要更换。找来一只相似的管座焊好后通电试机,发现屏幕为高亮度的蓝屏,并有回扫线,用万用表测三枪阴极电压,发现蓝枪阴极电压降为零,取下管座再测此极电压,恢复正常。用万用表欧姆档测显像管管脚 Symptom: Power off the image defocused, gradually become clear. Analysis and Maintenance: This is a common fault, can determine the video tube socket problems, need to be replaced. Find a similar socket after welding power test machine and found the screen for the high-brightness blue screen, and the flyback line, with a multimeter measured three gun cathode voltage and found that the blue gun cathode voltage drop to zero, remove the tube Retest the pole voltage, back to normal. Use a multimeter ohm file to test the picture tube pin