If you need to replace a component in your microwave, it is important to take safety precautions and seek the help of a trained microwave technician. The high-voltage capacitor can contain a potentially fatal amount of electricity and must be discharged before handling. The magnetron and high-voltage capacitor cannot be fixed and may need to be replaced. Other components, such as a blown thermal fuse or thermoprotector, might be fixable but it is best to seek professional help if you are unsure about how to handle any internal components or issues.