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一、接触不良故障产生原因1.整机装配工艺不良。在彩电生产过程中,如发生个别元件焊接时引脚有污垢或有安装缺陷,元件引脚吃锡较薄,印刷铜箔有划痕,线路板固定不牢等问题。当机器到达用户手中时,经过多次搬运震动,就可能使那些隐患部位脱焊或铜箔断裂,引起接触不良故障。2.发热元件引脚出现裂纹。彩电电源电路、行场扫描电路中有部分元件(大功率管和集成电路)工作时发热严重,元件引脚受热膨胀,断电后冷却收缩。而它们又被散热片紧紧固定在线路板上,长期的冷、热变
First, the causes of poor contact failure 1. The whole assembly process is not good. In the color TV production process, such as the occurrence of individual components soldering pins dirt or installation defects, the components pin thin tin, printed copper foil scratches, the circuit board is not fixed and other issues. When the machine reaches the user’s hands, after repeated handling vibration, it may make those hidden parts of the desoldering or copper foil rupture, causing poor contact failure. 2. Heating element pin cracks. Color TV power circuit, field scanning circuit in some of the components (high power transistors and integrated circuits) work serious heat, the components of the pin thermal expansion, power cooling shrinkage. And they are firmly fixed on the circuit board heatsink, long-term cold and heat changes