The stepper drivers are the most delicate part of the Axis 3d printer and it is why we've also included a spare. Before opening, make sure that you are grounded (touch a large metal object) to avoid any chance of static damage.

Prepare the A4988 stepper drivers by removing them from their packaging and sticking the heat-sink to the black chip.

Make sure that the heat-sink is not touching any of the pins. Orient the fins of the heat-sink as shown.

Trimpot: Adjust the trimpot so that flat side is pointing left as shown in the second photo.