Most common questions used to investigate
Is your door switch working?
Is the display switch blank?
Is your microwave not heating?
Are the lights and timers working?
Did your microwave suddenly turn off?
Does your microwave turn on and immediately turn off?
Common conclusions
A faulty door switch can be the problem if your microwave is not working. This switch also called an interlocking switch, sends a signal to the other parts to turn on. In other words, if your door is locked, only then other parts will start working. A good way to check for faulty doors is to unplug the microwave and check the terminals with a multimeter. If there's no continuity, it's time to replace the door switch.
If the display switch is blank and the microwave doesn't turn on, it could point to problems with your ceramic fuse. This part is responsible for protecting your microwave's components during a power fluctuation and when this fails, the internal critical components will not get power. This fuse could fail due to a ton of reasons, so take professional help to identify the cause and fix the same for you.
Sometimes, your microwave will turn on, but it won't cook or heat the food and that's because a critical component called magnetron may be broken. This component is responsible for generating the heat needed to cook food and if this component is broken, the chances for other components to fail are also high. The solution is to replace the microwave's magnetron.
This is a tricky situation. Your microwave turns on with the lights and timers, but your food doesn't get cooked. One of the reasons for this problem is a faulty diode. This part is responsible for converting the TC power from your outlet to DC power for the microwave and if this diode burns out due to power fluctuations or wear and tear, the magnetron will not get the power needed to generate the heat to cook your food. So, if you fix or replace the diode, your microwave should start working again. But, never do this by yourself unless you're an expert as it can store about 5000 volts of electricity.
Many times, your microwave may be working and it can suddenly turn off and not turn back on again. This can happen due to many reasons, but more likely due to power fluctuations. As a first step, check the GFCI switch as it could be tripped. Next, is to check the circuit breaker box to see if it was tripped. You can do this with the help of a multimeter or if you're not sure, take professional help for the same. Be careful as this can discharge high voltage. Once you identify the tripping, reset the power and you should be good.
It could be due to a failed control board that needs to be replaced.
Check the other critical components to get to the root cause.
References
Related Problems
