Microwave shows E3 and will not start or stops mid-cycle without heating.
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: The high-voltage section of a microwave (magnetron, transformer, capacitor, diode) can store lethal voltage even when unplugged. Do not attempt HV repairs unless you are trained and equipped to safely discharge capacitors.
- Basic checks only:
- Unplug the microwave.
- Inspect the interior cavity and waveguide cover for burns, arcing, or metal objects that may have caused a fault.
- Ensure no metal containers, foil, or twist ties are used when testing.
- Power reset: Unplug for 10 minutes, then plug back in and test. If E3 returns immediately, an internal HV fault is likely.
- Listen during operation: If the unit runs but does not heat and E3 appears, the magnetron or HV components may be failing.
- Do not bypass safety devices: Never bypass door switches or thermostats to clear E3.
Because of the high risk, replacement of the magnetron, HV transformer, capacitor, or diode in Black+Decker microwaves should be performed by a qualified appliance technician.