Depending on the type and severity of the issue, repairing a microwave without calling a professional technician is possible. People who are not professionals can fix some common issues, such as a microwave that doesn't run or uneven cooking results, by following online guides and by replacing any broken parts.
A microwave that does not turn on, for example, can result from a blown fuse, a bad door switch or a broken fan. A common volt-ohm meter can diagnose each of these problems by detecting how much voltage is running through each spare part. Making sure the appliance is off and the internal capacitor is discharged is important before anyone attempts to repair a broken microwave.