How do you know if a fuse is blown in your microwave?

Determining whether the primary ceramic high-voltage or line fuse inside a residential microwave oven has blown involves performing a continuity test with a digital multimeter. First, unplug the microwave from the wall outlet and wait several minutes for high-voltage capacitors to discharge safely. Second, remove the outer metal cabinet housing and locate the fuse holder near the power cord entry or transformer. Third, pull the fuse out and test it with a multimeter set to the ohms or continuity setting. You can troubleshoot microwave power failures safely. You can verify that your fuse is blown when the multimeter registers an open circuit (OL) with zero continuity, confirming that you must replace the blown fuse with an identical amp and voltage rating to restore electrical power.