The microwave oven time delay fuse is used to shut off the microwave if there is a power surge in order to protect it from damage. It is white in the centre and metal on both ends. This is a 20-amp fuse and is used to power your microwave. If the touch pad on the microwave becomes unresponsive, the microwave produces little to no heat, or the appliance simply does not turn on, it could mean that your fuse is faulty and needs to be replaced. Once your microwave's top grill and control panel are removed, you should see the fuse. A fuse simply pops in and out, but you need an exact match for your model of microwave.