Press the "Clear" key on the microwave and restart the machine if fault code "F1" appears on the display. It indicates that the microwave did not reach least 165 degrees Fahrenheit within 20 minutes of cooking due to a load's cold temperature. This may have happened if you tried to cook a large load when it was very cold or frozen.
Turn off the microwave and unplug it from its power source if fault code "F2" appears on the display. Fault code "F2" displays when a power surge occurs. Wait one minute, plug the machine back in, and then turn it back on.
Read the fault code on the microwave display panel if different than indicated in the above steps, and refer to your owner's manual to interpret the error. Follow the recommended suggestions for the repair. If your microwave does not work correctly, go to the next step.
Verify that the cookware is correct for the type of food you are cooking if it appears to be undercooked or overcooked. For example, most baked foods should be prepared on an appropriate baking dish or the black metal baking sheet or tray that is included with your machine. The tray is then placed on the glass microwave tray.
Check the voltage and verify that the circuit is sufficient based on your model's voltage requirements. Reset the circuit breaker if it has tripped. However, it it trips repeatedly, stop troubleshooting and contact a qualified electrician.