Microwave display shows E3 and unit stops heating shortly after starting, often with a humming sound.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Critical safety warning: High-voltage components inside a microwave (transformer, capacitor, diode, magnetron) can be lethal. Do not attempt HV repairs unless you are trained and equipped to safely discharge capacitors. For most users, E3 should be handled by a professional.
Basic user checks (no cabinet removal):
- 1. Confirm symptom: Start a short cook cycle with a microwave-safe cup of water. If E3 appears and the water remains cold, note the time to failure and any unusual noises (loud buzzing, arcing).
- 2. Inspect interior: Look for burn marks, arcing spots, or a damaged waveguide cover (mica sheet on the side wall). A burnt or carbonized waveguide cover can cause arcing and trigger HV faults.
- 3. Replace waveguide cover if damaged: If the mica cover is burnt or cracked, remove it (usually a single screw or clip) and replace with a Logik-compatible waveguide cover cut to size. Do not operate without a cover.
Advanced checks (for qualified persons only):
- With the unit unplugged and capacitor safely discharged, test the high-voltage diode and capacitor with appropriate methods, and inspect the magnetron for burn marks or cracked ceramic insulators.
Recommendation: Due to the danger of HV work, most users should contact a professional technician or authorized Logik service center for E3 faults.