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2.故障检修视频放大器发生故障在屏幕反映的现象繁多,常见有:无光栅、只有单一基色光栅、图像缺基色、图像偏色、关机亮点等。实例2 故障现象:开机收看不久屏幕亮度逐渐增且偏蓝色,随后画面变大变亮满幅回扫线,接着“吱”的一声,电视机自动关机。分析检修:从故障现象来看问题出在蓝输出级,原因是电路中元件热稳定性变差。直观查看蓝输出管Q358、Q361,发现蓝电子枪阴性回路电阻R390及PNP管发射极电阻R384表面焦黄,显然这是阴性电
2. Troubleshooting video amplifier failure on the screen reflect the phenomenon of many common are: no grating, only a single primary color grating, the lack of image color, image color cast off the bright spots and so on. Example 2 Symptom: start watching the screen brightness gradually increased and partial blue, then the picture becomes larger fullback flyback line, then “squeak”, the TV automatically shut down. Analysis and maintenance: From the point of view of the fault phenomenon in the blue output stage, because the circuit components in the thermal stability of the worse. Intuitive view of the blue output tube Q358, Q361 and found that the blue electron gun negative loop resistance R390 and PNP tube emitter resistance R384 surface yellow, apparently this is negative electricity