论文部分内容阅读
故障现象:一台春风IC-141黑白电视机,伴音正常,有回扫线,无图象,亮度电位器开足时整个屏幕布满大白点状干扰。故障分析及检查:伴音正常,有回扫线,无图象,故障一般出在视放末级及中压整流电路。经检查:D7611AP各脚电压正常,视放末级管5BG_1集电极电压从68V升到125V,中压从l00V升到145V。有伴音说明D7611AP工作正常(特殊情况除外),有回扫线、无图象是5BG_1截止,使图象、消隐信号难以加到显象管的阴极。另外D7611AP中的预视放和5BG_1损坏不会引起“大白点状干扰”(约5mm大),根据现象又检
Symptoms: A spring breeze IC-141 black and white TV, sound normal, there are retrace lines, no image, the brightness of the potentiometer open the whole screen full white spot interference. Failure Analysis and Inspection: Normal sound, a retrace line, no image, the failure is generally seen as the final level and the voltage rectifier circuit. After checking: D7611AP normal voltage of each pin, depending on the end of the tube 5BG_1 collector voltage rose from 68V to 125V, medium voltage rose from l00V to 145V. Have a sound that D7611AP work properly (except for special circumstances), a retrace line, no image is 5BG_1 end, so that the image, blanking signal is difficult to add to the CRT cathode. In addition D7611AP in the pre-amp and 5BG_1 damage does not cause “white point interference” (about 5mm big), according to the phenomenon again