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本文以广泛应用的A3机心电源为例(图可参见各厂家A3电源),谈谈彩电开关电源的安全检修方法。其他并联开关电源基本相同。电源安全检修步骤:第一步,用“在路测量法”检查二、三极管正、反向电阻值,各路输出电压端对地正、反向电阻值,判断有无明显坏元件?当有明显损坏元件时应及时更换。第二步,断开所有电源负载(注意:A3机心+B电源电压为130 V)、反馈稳压,断开时应在A点以后断。较安全方法是:断开“行管”c极供电,将开关管发射极电阻拆下(对于开关管发射极直接接地的电源电路,可断开发射极接线),找一只阻值为30～50 Ω/0.5 W电阻,串入发射极(注意:此时不能接假负载),串入此电阻的目的是利用其深度负反馈来,保护开关管不被烧坏。第三步,通电检修。当上述工作完成后,即可开机
In this paper, a widely used A3 core power supply as an example (see Figure A3 manufacturers can power), talk about the color TV switching power supply security overhaul methods. Other parallel switch power is basically the same. Power supply security steps: The first step, with “in the way of measurement ” check two, the transistor positive and reverse resistance, the output voltage of each terminal is positive and negative resistance value, to determine whether there are obvious bad components? When there is obvious damage to the components should be promptly replaced. The second step, disconnect all power load (Note: A3 heart + B power supply voltage of 130 V), feedback regulator, disconnect should be broken after A point. A safer method is: Disconnect “line tube ” c pole power supply, the switch emitter resistor removed (for the switch tube emitter directly grounded power supply circuit, disconnect the emitter wiring), find a resistance 30 ~ 50 Ω / 0.5 W resistor, string into the emitter (Note: At this time can not take the dummy load), the purpose of stringing in this resistor is to use its depth negative feedback to protect the switch tube is not burned. The third step, power maintenance. When the above work is completed, you can boot