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例1 夏华VCD-168型故障现象:插上电源插头无任何反应。分析与检修:此故障首先应检查电源部分。打开机盖检测电源变压器次级输出电压均正常,测YDS-ZIZ低压开关电源集成组件、脚输入、输出电压也均正常。但测到降压二级管D_(508)正极约有9.8V;而负极只有2V左右。关断电源D_(508)正反向电阻已近断路,换上同型号二极管1N5391后,机器故障消除。例2 爱多IV-720A型
Example 1 Xia Hua VCD-168 type Symptom: Plug in the power cord without any reaction. Analysis and Maintenance: This problem should first check the power supply section. Open the lid detection power transformer secondary output voltage are normal, measuring YDS-ZIZ low-voltage switching power supply integrated components, the input pin, the output voltage is normal. However, it is found that the voltage of the diode D 508 in the step-down diode is about 9.8V, while the negative electrode has only about 2V. Turn off the power D_ (508) Forward and reverse resistance is almost open circuit, replace the same model diode 1N5391, the machine fault eliminated. Example 2 love more IV-720A type