Microwave Fuse Blown? How to Diagnose and Replace It

If your microwave suddenly stops heating or won’t turn on, the first thing to suspect is a blown fuse. It’s cheap, easy to test, and often the only part that needs swapping. Below you’ll find a straight‑forward guide to spotting a bad fuse, changing it safely, and deciding when it’s time to call in a professional.

Check the Symptoms

Before you tear the microwave apart, make sure the problem really is the fuse. Typical signs of a blown fuse include:

  • The microwave powers up but shows no heat.
  • The display lights up but the turntable doesn’t spin.
  • Nothing happens at all – the unit is completely dead.

If you notice any of these, unplug the microwave and move to the next step. Never try to test a fuse while the appliance is still plugged in – it’s a shock risk.

Most microwaves use a ceramic or glass cartridge fuse rated between 15‑20 amps. You can usually find the exact rating printed on the fuse itself or in the user manual.

Replace the Fuse Safely

Here’s a quick, no‑fuss method to swap the fuse:

  1. Unplug the microwave. Make sure the power cord is completely disconnected from the wall.
  2. Locate the fuse. It’s typically behind the outer cover or under the cord entry panel. You may need a screwdriver to remove a few screws.
  3. Inspect the fuse. Look for a broken filament or a darkened glass body. If it looks intact, test it with a multimeter set to continuity – a good fuse will beep or show zero resistance.
  4. Get the right replacement. Match the amperage and voltage rating exactly. You can buy a generic microwave fuse from most hardware stores or online – they’re usually under £5.
  5. Insert the new fuse. Snap it into place, re‑secure any panels you removed, and double‑check that everything is tight.
  6. Plug the microwave back in. Test a short run to see if heat returns. If it does, you’ve saved yourself a call‑out fee.

If the microwave still won’t heat after a fresh fuse, the issue could be the magnetron, high‑voltage diode, or control board. Those parts need a qualified technician.

Some extra tips:

  • Always wear insulated gloves when handling internal components.
  • Keep a small flashlight handy – interior lighting is often dim.
  • If the fuse blows again within a few weeks, stop using the unit and get a professional diagnosis. Repeated fuse failures point to deeper electrical problems.

Replacing a microwave fuse is one of the few DIY repairs that most homeowners can do safely. With the right tools and a bit of patience, you’ll have your microwave humming again in under 15 minutes. And if you ever feel unsure, a quick call to a local repair service – like Nuneaton Appliance Repair Experts – can give you peace of mind without breaking the bank.