Microwave problems

If it runs, lights up and turns but doesn't heat, the usual causes are a failed magnetron (the part that makes the heat), a high-voltage diode, or a high-voltage capacitor. A worn door switch can cause it too.

Unplug it, or switch off its breaker for over-the-range models, for about a minute, then plug it back in. Pressing Cancel or Stop twice clears a stuck program. If it still won't work, the usual causes are a blown internal fuse, a door switch, or the control board.

Without metal inside, sparking usually comes from a burned or greasy waveguide cover (the small panel inside the cavity wall), chipped paint inside the cavity, or a failing magnetron. Stop using it until it's checked.

If it's completely dead, the usual cause is a blown internal fuse, often from a failed door switch. If it has power but won't start, the usual causes are a door switch or the control board.

The usual causes are a failed door switch, a shorted high-voltage capacitor or magnetron, or a failed turntable or fan motor.

A door that won't open or close usually has a broken door hook or latch spring, a worn door release button or lever, or a misaligned door. The door switches work with the latch, so a door that doesn't latch properly often stops the microwave from starting.

Most microwaves remind you with a beep when food is left inside. If it beeps with the door closed and nothing inside, the usual causes are a stuck button on the touchpad, the control board, or a door switch.

The usual causes are a door switch that loses contact, a thermal cutout that trips because the magnetron is overheating, or a failing control board.

Over-the-range and built-in microwaves are usually worth repairing: door switches, fuses, magnetrons and latches are replaceable. A small countertop microwave usually isn't.

If the plate is seated correctly on its roller ring, the usual causes are a failed turntable motor, a worn coupler under the plate, or a turntable that's been switched off on models that allow it.

A light that stays on after the door closes usually means a door switch isn't changing position. The usual causes are a failed door switch, a door that isn't closing fully, or a relay on the control board.

Over-the-range microwaves turn the fan on by themselves when the cooktop below gets hot, to protect the electronics. If it runs with the cooktop cold, the usual causes are a failed thermal sensor, a relay on the control board, or the fan switch.

It's a reminder to clean the grease filters under an over-the-range microwave. Clean them, then clear the reminder with the button your model's manual lists. If it keeps coming back right away, the usual cause is the control board.

The internal fuse is there to blow when something else fails. The usual causes are a failed door switch (often the monitor switch), a shorted high-voltage capacitor or diode, or the magnetron.

The usual causes are a broken door hook or latch spring, a door that has dropped out of alignment, or a damaged door frame.

A loud hum or buzz while heating usually comes from a failing magnetron or high-voltage transformer. Grinding or rattling is usually the turntable motor or the fan.

Stop using it until it's checked. Beyond burnt food, the usual causes are a burned waveguide cover, overheated wiring, or a failing magnetron.

It depends on the brand. See our microwave error codes page, or tell Switch the brand and the code.

Start with what it does:

• Runs but no heat: magnetron, diode or capacitor.
• Completely dead: fuse or door switch.
• Sparking: waveguide cover or magnetron.
• Door won't open: latch or hook.

RepairNow connects you with vetted, independent technicians in Austin, Round Rock, Georgetown, Cedar Park, Leander, Lakeway, Bee Cave and Dripping Springs. Start with a free online diagnosis, then book: before 2 pm for same-day service; after 2 pm, we'll get someone to you within 24 hours.