Cut the damaged plug with pliers. Generally speaking, if it is determined that the plug is damaged, it can be cut along the root of the plug to keep the wire as much as possible.
Use wire stripping pliers to strip the insulation sheath at the end of the wire about 5 mm, exposing the internal metal conductor.
If you don't have a wire stripper, you can use a nail clipper or a utility knife.
Generally, the inside of the earphone cable is enameled wire, not the plastic insulation layer shown in the figure. For enameled wire, please use sandpaper to polish off the insulating paint on the surface of enameled wire and scrape it lightly, but try not to use fire to avoid copper oxidation affecting welding.
The electric soldering iron is electrified and preheated, and the common electric soldering iron can reach the welding temperature in about 2-3 minutes.
If there is rosin, it is suggested to put the peeled thread into a rosin box and heat it with a soldering iron for one or two seconds to melt the rosin and stick it to the thread. Rosin is a kind of flux, which can improve the weldability of metals, but please be careful not to inhale the smoke generated when rosin is heated. The picture below shows a common rosin block, which can be bought in shops selling electronic components and musical instruments (erhu, violin and other stringed instruments also use it).
8. Use pliers to clamp the large metal sheet of the male * * * wire flat, so that the wire can be firmly pressed to prevent external force from acting on the wire and causing desoldering.
9. Finally, screw on the shell and test it on the computer.