1、 Because of the small size of the USB female connector, the four pins of the USB interface are generally difficult to weld, and if the distance between the pins is too close, the two pins may be welded together without attention. In the face of this situation, you can wipe the solder pin with flux before welding, and pay attention not to stick too much flux, because it is difficult to wipe off in the later stage, and the effect of flux is not only to make the welding more smooth, but also to fix the USB port, which is not easy to shift during welding.
2、 After coating the flux, clean the tin on each solder joint with a soldering iron. The purpose is to prevent excessive tin, so as not to cause false soldering. At this time, only a little tin is left on the surface of the solder joint.
3、 Then put the USB female connector on the pad, put it in the alignment line position gently, press the pin with a soldering iron at this time, and wait for a few seconds, then it can be welded.
4、 In the welding of USB bus connector, we should pay attention to the operation force is not too large, to avoid causing the pin of USB bus to be easily bent by force, showing uneven situation on the pad, resulting in false welding or false welding.
5、 Note that after the final welding, it is necessary to check whether the welding is completed by measuring the diode with a multimeter. For example, whether there is looseness or false soldering in the pin, if there is, repeat the soldering.