Microwave displays E15 and stops; a loud humming noise may be heard before shutdown.

Critical safety warning: High-voltage components are extremely dangerous. Do not attempt to test or replace HV parts unless you are trained and equipped to safely discharge the capacitor.

• Step 1 – Stop using the microwave: Unplug immediately if you hear loud humming or see sparks, and E15 appears.
• Step 2 – Visual inspection only: With the cabinet removed, look for obvious burn marks or melted insulation near the HV transformer, capacitor, diode, and magnetron. Do not touch these parts.
• Step 3 – Inspect waveguide and cavity: From inside the cavity, remove the mica cover (if fitted) and check for burn-through or carbon tracking. Replace a damaged mica cover and clean carbonized areas.
• Step 4 – Professional repair: Have a qualified technician test the HV capacitor, diode, and magnetron, and replace any shorted components.