Today, several prototypes are manually welded, and the direction of the main CPU of a Board is incorrect. This CPU is a 144 pin surface mount device, and many pins will be welded. in order to remove it, I spent a lot of time thinking about it. This article referred to the paper <disassembly and welding of surface SMD components>. As this paper only describes the content in the text, so I have the idea of writing a graphic article about removing surface mount elements.
1. Prepare a wire or patent Wire
2. Take the wire core. Note that the wire core must have a certain diameter, which is roughly the same as the diameter of the CPU pin.
3. Pass a wire core through the inside of the CPU pin
4. one end of the wire core is fixed on a nearby pad.
5. use a soldering iron to heat the CPU pin and pull the wire core outward at the same time. The wire core has a certain angle up, about 20 or 30 degrees. This way, after pulling the wire core from the CPU pin, it can tell that the CPU pin is slightly tilted up, remove from pad.
6. Remove other three sides in the same way
Note: The soldering iron cannot be overheated, and the contact time with the CPU pin cannot be too long.
After completing the operation, you can clean it if necessary.