Starting from the most accessible wire, desolder the wires from the circuit board one by one.

Make sure that the tip of the soldering iron is clean of all residue before starting.

Heat the soldering iron only to the temperature required to melt the solder. Check the specifications on your spool of solder for the correct temperature.

Once all of the wires have been desoldered from the circuit board, remove the circuit board completely from the drill.