White countertop microwave on a kitchen counter

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Microwave shuts off by itself during cooking

Mid-cook shut-downs usually mean a thermal cutout is opening because the cooling fan failed or the vents are blocked, or a marginal door switch is opening. Check airflow and installation first, then the fan, cutouts and switches with the HV capacitor discharged.

Single source ~45 min advancedBrands: All

Before you start

DANGER: the HV capacitor can hold a lethal charge even when unplugged
Untrained users must not open the cabinet
Trained techs: unplug, discharge with an insulated tool and verify 0 V before internal tests

Diagnostic steps

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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