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笔者在检修多台长虹2128FB彩电中,发现“无字符显示”故障为该型机存在的“通病”,且故障率较高,多发生在使用一二年后的机器上。根据现象分析,故障应出在字符发生电路。应着重从CPU(CHT0807)的(28)、(29)脚字符振荡电路和(26)、(27)脚的字符定位行、场脉冲入手。实测CPU(26)、(27)脚(行、场脉冲输入)电压正常,而(28)、(29)脚的对地电阻值变小、电压偏低,经查故障系CPU字符振荡“中周”L001内附瓷管电容C017变黑漏电所致。
I overhaul more than Changhong 2128FB color TV, I found “no character display” failure of the machine exists “common problem”, and the failure rate is high, occurred in the use of a machine two years later. According to the phenomenon analysis, the fault should be in the character generating circuit. Should focus on the character from the CPU (CHT0807) (28), (29) foot character oscillator circuit and (26), (27) pin character positioning lines, field pulse start. Measured CPU (26), (27) feet (line and field pulse input) voltage is normal, and (28), (29) feet of the resistance value becomes smaller, the voltage is low, Week "L001 included ceramic tube capacitor C017 black leakage caused.