Unplug the microwave's power cable from the wall outlet.
Remove the two screws on from the left and right sides of the front of the grill on the top of the microwave.
Remove the grill by pulling straight out.
Remove the screw located on the top of the control panel. Lift the control panel out of the microwave.
Label the wires connected to the rear of the control panel for easy reassembly, then unclip the wires connected to the rear of the control panel.
Locate the fuse, which is located in the compartment that was covered by the control panel.
Pull the fuse out of its holder and examine to ensure that the fuse is blown. If the fuse is blown, burn marks will appear on the inside of the glass, or the glass will be completely black.
Insert the new fuse into the fuse slot.
Reconnect the control panel wires, then insert and secure the control panel using the screw that was originally removed.
Reattach the grill and secure it using the two screws that were removed.
Restore power to the microwave to complete the installation process.