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[例7]长虹N2918彩电,VCC+115 V电压一会儿正常,一会儿为0 V。分析与检修:VCC+115 V电压正常时,测量TEA2261各脚电压正常,说明TEA2261、电源启动电路工作正常,造成此故障的原因可能是开关管Q801周围电路及开关变压器T803有故障。更换开关变压器,故障末排除。检查Q80l周围器件,发现R820阻值变大,从而造成过流保护电路误动作,使电源停止工作。更换R820后,故障排除。[例8]长虹N2516彩电,空载时,开关电源输出
[Example 7] Changhong N2918 color TV, VCC + 115 V voltage normal for a while, while for 0V. Analysis and Overhaul: When the voltage of VCC + 115 V is normal, measure the normal voltage of each pin of TEA2261, which indicates that TEA2261 is working normally. The cause of this fault may be that the surrounding circuit of switch Q801 and the switch transformer T803 are faulty. Change the switch transformer, the end of the fault excluded. Check Q80l around the device and found R820 resistance becomes larger, resulting in over-current protection circuit malfunction, so that power to stop working. After replacing the R820, troubleshooting. [Example 8] Changhong N2516 color TV, no-load, the switching power supply output