In retrospect, what would become of your short snack break in between tasks if microwaves wouldn’t be invented in the first place? I suppose it would be anything but hot. A similar situation is recreated when the microwave fails to work despite having power. A microwave can break down once in a while, regardless of its make and quality. One common problem faced by most microwaves is the appliance receiving power but does not work. What causes this issue, and how can you fix this problem?
When you notice your microwave receiving power but not heating, you need to carry out a full diagnosis to identify where the faults come from your appliance. The process of troubleshooting a microwave that powers without heating involves eliminating some of the most common technical issues. When you troubleshoot your appliance yourself, you will save both time and repair costs. The out of warranty repair visits from an appliance repair can be costly, more so, if the issue is simple enough for you to handle on your own. A lot of the issues causing your microwave to receive power but not heat are easy to fix without necessarily having special skills.
What Causes Your Microwave not to Working despite Receiving power?
The first step towards restoring your faulty microwave back to its optimum efficiency is to determine its point of weakness. This begins by understanding the possible causes of faults within your appliance in the first place. Some of the common issues leading to a microwave that does not work but receives power include:
Faulty Line Fuse
The first reason why your microwave might be receiving power but not heating is a faulty line fuse. The line fuse often blows when more current than expected flows through the microwave circuitry. When this happens, your unit will receive power but not heat. To determine if this is the cause of your microwave’s inability to heat, you need to use a multimeter (view on Amazon) to check for continuity.
If the fuse has no continuity, you should change it for a new, proper functioning piece. Additionally, you need to find out the true reason why your appliance’s fuse blew and fix it. Ensure you exercise all the necessary precautionary measures when dealing with an electrical appliance to protect yourself against electrocution. Contact a qualified electrician to help you troubleshoot and fix your microwave if you do not feel comfortable working with electrical appliances.
Broken Main Control Board
Your microwave may also not work because of a faulty main control board. This is mostly caused by a power issue within the main control board. In some cases, however rare, the main control board may develop defects. Ensure you inspect your appliance’s main control board after checking all the other parts. Ensure all the other parts of the microwave are in excellent working condition before accessing the main control board and checking it for continuity using a multimeter.
Faulty Thermal Fuse
When your microwave has a faulty thermal fuse, it is likely not to heat. The thermal fuse is responsible for cutting off the power supply to your appliance when it becomes overheated. For you to know whether the thermal fuse has blown or not, you need to use a multimeter and check for continuity. If there is no continuity, you need to replace the fuse with a new, proper functioning unit. However, you will have to search for other issues if it has continuity.
High Voltage Diode
Your microwave may fail to heat despite receiving power as a result of high voltage diode. This component of your microwave powers up the magnetron.
Steps for Testing the High Voltage Diode Using a Multimeter (view on Amazon)
- Disconnect your appliance from its power source before you start working on it
- Find and remove the high voltage diode for testing. You will have to test it for continuity. To access this component, you first have to remove the appliance’s cabinet and discharge its high voltage capacitor.
- With your multimeter settings at Rx1, touch its probes to the terminals. Follow this up by reversing the probes to inspect continuity in the opposite direction. Your multimeter should show a reading in one direction and not a different direction.
- If your high voltage diode shows continuity in a different direction or does not show continuity, you will have to replace it.
Most microwaves with broken magnetrons may not heat up. The magnetron is a part of your microwave that makes the appliance to heat and cook food. A broken magnetron could blow your fuse, which might result in the failure of other components.
Steps for Testing the Microwave Magnetron with a Multimeter
- Disconnect your microwave from its power source. Double-check to ensure the appliance is completely disconnected.
- Remove the microwave’s cabinet for you to access the magnetron.
- Discharge your appliance’s high voltage capacitor before verifying if your high voltage diode is working in a perfect condition. You should also inspect its mounting bolts to ensure they are fixed tightly.
- Remove the magnetron for testing. Test it to ensure it has no other issues.
- Set your multimeter on Rx1 and touch its probes to the terminal. The multimeter should record a resistance ranging between two or three ohms.
- Put one probe on the magnetron’s metal housing. There should be no reading for continuity.
- Replace the magnetron if your results do not match what is recommended in this article.
When your microwave’s door switch is broken, it will most likely power but fail to heat. The door switch is intricately linked to all other parts of the microwave. When the door is closed, the door switch sends a signal to all the other parts of the appliance to supply power and heat up. It sends another, but different signal when the door is opened. In this case, the door switch tells all the other parts of the appliance to stop heating.
A microwave’s door switch is also known as an interlock switch. When it fails, the appliance’s stirrer motor and fan may function properly, thus making your microwave to appear like it is functioning properly.
Steps for Testing the Microwave Door Switch with a Multimeter
- Start by disconnecting the microwave from its power source.
- Examine your appliance’s door hook to ensure it triggers the door switch mechanically. When they do, you need to remove your appliance’s cabinet, find the door switch, and remove it for testing. This test should be for continuity.
- Set your multimeter on Rx1. Touch its probes on the switch’s terminal as you press the actuator button. The expected result from this test is zero, indicating continuity.
- If the result obtained from this test is not similar to the expected result, you need to replace your appliance’s door switch.
Microwave Turns on and Immediately Turns Off
Your microwave could turn on and immediately turn off for several reasons. This often happens within a few seconds after the start of the operation. Some of the reason why this happens includes:
- Failing main control board
- Damaged door switch
- Broken touchpad
- Damaged high voltage transformer
- Tripped thermoprotector (view on Amazon)Defective thermostat
Use a multimeter to check fuses, switches, and parts through which electric current flows. Check for continuity. You need to replace all the faulty parts.
Your microwave is not heating for any one of these reasons. Use this guide to troubleshoot and fix your appliance. Repair the microwave to restore it to its optimum function. Do not hesitate to call a qualified appliance repair if you encounter a difficult problem that needs a skilled set of hands. In addition to this, you should consider replacing your old microwave with a new unit.