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故障现象:一台采用韩国高士达电路的凯歌4C51C彩电,伴音正常,但无光栅。检修记实:开机观察故障现象后,在关机的瞬间,屏幕上有光亮一下,由此判断,该机的电源、行输出等电路正常,估计故障在视放电路,因此对视放电路进行重点检查,当测到R、G、B三个信号的输入端电压时,发现电压明显偏低,已由正常的3.5V下降到1V左右。视放板上的R、G、B信号分别来自色度、亮度信号处理集成电路TDA3562A的⒀、⒂、⒄脚,为了进一步判断故障,断开了集成电路TDA3562A的⒀、⒂、⒄脚
Symptom: a high-end circuit with a song of Korea Kay 4C51C color TV, sound normal, but no grating. Maintenance record: Power failure observed after the shutdown moment, there is light on the screen, which determine the aircraft’s power supply, such as the normal output circuit, it is estimated that the fault in the visual circuit, so focus on the circuit as the release circuit Check, when measured R, G, B three signal input voltage, the voltage was significantly lower, from the normal 3.5V down to about 1V. The R, G and B signals on the video board come from the ⒀, ⒂ and ⒄ pins respectively of the TDA3562A of the chrominance and luminance signal processing integrated circuit. In order to further judge the fault, the T, ⒂ and ⒄ pins of the integrated circuit TDA3562A are disconnected