Pull the plug on the Harmony's power cord from the wall outlet. Wait for the appliance to cool to room temperature.
Take out the screws in the service panel on the back of the Harmony, using the screwdriver. Pull off the panel to find the fuse mounted along the top of the round heating element case. The fuse is on a white metal plate.
Pull off the crimped connectors on the end of the wires attached to the fuse contacts. Remember which wire attaches to which contact.
Remove the two screws in the mounting plate below the fuse to remove the part.
Set the new fuse onto the heating element and attach with the two screws.
Slide the wires onto the two fuse contacts.
Replace the service panel, and attach it with the screws.
Plug in the Harmony's power cord.