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长风CF47C—2型彩电,伴音正常,荧光屏出现全绿光栅,有淡回扫线,同时亮度失控。检修:用万用表测量三个输出管集电极电压,正常时Q_(505)、Q_(507)、Q_(509)的集电极电压均为108V;现测得Q_(505)、Q_(509)为180V,比正常值偏高,Q_(507)为90V;比正常值偏低。拔下尾板再测量三个输出管集电极电压为原数值,说明显像管无问题,故障在末级输出电路或解码电路。插上尾板测量TA7698各点电压正常,集成块是好的,确认问题出在末级输出级,拔下尾板,测三个末级输出管,各可调电阻均良好。再测三基色信号电阻发现
Changfeng CF47C-2-type TV, sound normal, the screen appears full green grating, a light back line, while out of control brightness. Overhaul: Use the multimeter to measure the collector voltage of the three output tubes. The collector voltages of Q_ (505), Q_ (507) and Q_ (509) are both 108V at normal time. Q_ (505) and Q_ 180V, higher than normal, Q_ (507) is 90V; lower than normal. Unplug the tailgate and then measure the three output tube collector voltage to the original value, indicating that there is no problem with the picture tube, and the fault is in the final output circuit or decoding circuit. Insert the tail board measurement TA7698 voltage normal, manifold is good, confirm the problem is in the final output stage, unplug the tail board, measuring the three final output tube, the adjustable resistance are good. Then test the three primary color signal resistance found