False welding refers to the fact that the welding on the surface of the solder joint seems to be successful, but it is not actually welded. Sometimes the lead can be pulled out of the solder joint with a single pull; and the virtual solder is a small amount of solder pillar at the solder joint. Causes poor contact, continuous on and off. My understanding of the false soldering and the dummy soldering is that the dummy soldering is not actually soldered and the device cannot be used, while the dummy soldering is not reliable soldering, and there will be good and bad situations when the contact is bad.