Shut down the printer and unplug the power cable.
Remove the four foot pads and two fixing screws by using the hex wrench.
Remove the fan cable from the mainboard and remove the cover.
(Note: Take the cover carefully to avoid pulling the fan wire)
Use the pliers to remove the yellow glue from the terminals. Remove all cables from the mainboard, and the four screws securing the mainboard.
Remove the faulty mainboard and replace it with a new one. Tighten the four screws that secure the mainboard.
Refer to the following wiring diagram.
Plug in the fan terminal of the mainboard, and close the bottom cover.
(Note: The cable routing of the mainboard fan)
Tighten two screws to secure the bottom cover and install four foot pads.
Plug in the power cord, power on and check the startup.