As the drive circuit board are programmable chips, circuit board repair so hard not just "soldering iron" and "solder" work, but also the use of specialized programming equipment.

Try not to touch the surface of the copper after etching either or you'll get oils on it and it will be hard to solder.

The damage styles of cast-in cutting pick and hard-solder forging cutting pick are analyzedaccording to the comparing experiment under coal mining well.