In replacing a Sharp microwave fuse, the appliance must be unplugged and the back cover removed using a screwdriver. The fuse is a small glass cylinder capped with metal on either end; once it is disconnected from the wires holding it in place, it can be replaced.
If the fuse is not clearly visible once the back of the appliance has been removed, it is may be situated beneath the unit's control board, which is located under the exhaust vent at the top of the appliance. The vent is held in place by a single screw; the control board should be gently lifted from its housing and disconnected while making to sure to make note of all the connectors to the panel so they can be reconnected.
Owners unsure whether the fuse is root of the problem can use an OHM meter to identify whether voltage can pass through the component; the fuse must be removed from the unit before it is tested with the meter.
While small and inexpensive, the part is critical to the operation of the microwave, as a bad fuse halts its entire operation. Replacement Sharp fuses organized by microwave model number can be purchased through SearsPartsDirect.com or RepairClinic.com.