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[例1]故障现象 一台索尼KV-1882CH型彩电,白天工作正常,到晚上七八点钟左右就常出现开机启动困难现象,一旦启动则工作正常。 分析与检修 从现象上分析,故障原因似乎是电源启动回路受电网电压的影响较大。首先用自耦调压器向电视机供电,证实该机最低启动电压为212V,且一旦工作,将电压调至150V时机器工作仍正常。打开后盖,测开关电源电路
[Example 1] Symptom A Sony KV-1882CH color TV, daytime work is normal, until about seven or eight o’clock in the evening there often appear difficult to start the boot, once started, then work properly. Analysis and maintenance From the phenomenon of analysis, the cause of the malfunction seems to be the power supply start-up circuit by the greater impact on the grid voltage. First of all, with a voltage regulator to the TV power supply, confirmed that the minimum starting voltage of the machine is 212V, and once the work, the voltage is set to 150V when the machine is still working properly. Open the back cover, measuring switch power circuit