At present, many household appliances and instruments use various chip components, but it is difficult to disassemble and weld without special tools. Here are the methods of disassembly and welding for your reference. 1. Tool selection: 1. Choose an internally heated long-life soldering iron of about 25w, which requires no leakage and moderate temperature (power and temperature are best adjustable). 2. The medical disposable syringe is provided with a small needle or a hollow stainless steel needle, and then the tail of the small needle is bent into a small hook. 3. Paper cutter or small scalpel. 4. Welding wire with a diameter of 0.62-0.8mm. 2. Dismantle 1. After the soldering head is filled with tin, remove the tin and clean it with a rag to ensure that the soldering head is bright and easy to use. 2. Use a pointed soldering iron to melt the solder on the IC pins of the chip one by one. When the solder melts, the pins are quickly stirred up one by one with a needle tool, so that the pins are separated from the pads on the printed board, and finally the whole integrated circuit is taken out. Third, welding 1. Clean the printed circuit board. Clean the place of integrated circuit with alcohol (especially rosin and solder residue). 2. Grind the welding surface of the new IC pin with fine sandpaper, and coat it with alcohol rosin solution, and line it with a thin layer of tin. 3. In order to prevent the integrated circuit from shifting during welding, the components can be pasted on the corresponding position on the printed board with epoxy resin first. After curing, brush the soldering flux on the pins to facilitate welding. 4. When welding, the method of spot welding can be adopted, and the welding time should be controlled within 3s. Generally, one or two pins at the four corners are welded first, and then the other pins are welded one by one. After all the pins are welded, gently dial the pins one by one with a small needle to check whether there is any virtual welding. Then use a magnifying glass to check whether there is a short circuit between the pins. Deal with problems in time. Finally, clean the pins with alcohol.