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1.李彦彬:《家电检修技术》第6期载许建荣同志《HFC—2175彩电7812稳压块不佳为何屡烧TDA3653B?》一文,笔者深有同感,我近日也修过一台相同机芯的HFC—2176福日彩电,先后烧毁了4块TDA3653B场输出块,最后才查出系7812接触不良引起的,更换后至今已有两个月,一直使用正常。 HFC—2176与HFC—2175同属F91PP机芯,该机芯电源部分为并联型自激式开关稳压电源,主电压+113 V输出端未加过压保护电路,而过压保护设在了行电路部分。由于该机芯的低压12 V全部由7812提供,一旦7812有接触不良或稳压效果不佳时,其输出的12 V电压发生波动或消失,将直接影响
1. Li Yanbin: “Appliance Maintenance Technology,” No. 6 Comrade Xu Jianrong “HFC-2175 TV 7812 poor quality control block repeatedly burning TDA3653B?” A text, I feel the same, I recently also repaired a same movement HFC-2176 Fukuda TV, has burned 4 TDA3653B field output block, and finally found the Department of 7812 caused by poor contact, has been replaced for two months, has been using the normal. HFC-2176 and HFC-2175 belong to the same F91PP movement, the power part of the movement of the parallel self-excited switching power supply, the main voltage +113 V output without over-voltage protection circuit, and over-voltage protection in the line Circuit part. Since the low-voltage 12 V of the movement is all provided by the 7812, once the 7812 has poor contact or poor regulation, the output of the 12 V voltage fluctuations or disappearance will have a direct impact