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我们乡电视差转台使用的山西运城无线电厂生产的“DCFY-10型”10W电视差转机,在几年使用维修中处理过几次由穿芯电容造成的故障,现记叙如下,供同行们参考。 1.机器没图像、伴音输出,观察末级功放管FU-19阴流表没指示,说明功放级没工作。测屏极电压450V,基本正常;测帘栅极电压只有25V左右。并且稳压管G_(302)没有辉光(见图1)。最后查出是穿芯电容C_(334)严重漏电,更换后整机工作恢复正常。 2.整机没输出。经粗略检查,初步判断故障出在中放部分。测中放各极屏极、帘栅极电压都很低;查检中
Our rural TV station using Shanxi Yuncheng Radio Factory production of “DCFY-10” 10W TV transfer machine, several years in the use of maintenance handled several times by the core capacitance of the fault is now described below for reference . 1. The machine did not image, sound output, observe the end of the power amplifier tube FU-19 did not indicate the counter, indicating that the amplifier did not work. Measured screen voltage 450V, basically normal; measured curtain gate voltage is only 25V or so. And Zener G_ (302) has no glow (see Figure 1). Finally, it is detected that there is a serious leakage current through the core capacitor C_ (334). After the replacement, the whole machine resumes normal operation. 2. The machine did not output. After a rough inspection, the initial judgment of the fault lies in part. Measured in the very pole, the screen voltage is very low grid; check