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故障现象:开机约几秒钟内图像、伴音正常,随后图像上下跳动,光栅变成水平一条亮线。分析与检修:该故障现象常见并不特殊,但笔者按照老式彩电检修思路、经验,开机数秒钟光栅正常(说明场振荡电路正常),误以为场输出集成电路N301(AN5534)③脚场交直流反馈W301可变电位器接触不良.其实小然,费了“九牛二虎”之力把N301外围折腾一遍,却一无所获。经查阅N701(AN5095K)内部方框图,分析认为故障系N701(20)脚外围ABL自动亮度控制电路异常所
Symptom: boot image within seconds, normal sound, then the image beats up and down, the grating becomes a bright line. Analysis and maintenance: The fault phenomenon is not uncommon, but I follow the old TV repair ideas, experience, boot a few seconds the grating normal (indicating field oscillator circuit is normal), mistakenly think that the field output integrated circuit N301 (AN5534) Feedback W301 variable potentiometer poor contact. In fact, a small, cost of “Nine Bears and Two Tigers,” the power to toss the N301 outside again, but nothing. After checking the internal block diagram of N701 (AN5095K), it is considered that the fault is the abnormality of ABL automatic brightness control circuit on the periphery of N701 (20)