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Why Is My Samsung Microwave Not Heating? Complete Repair Guide

If your Samsung Microwave is not heating then there may be an issue with the power supply, the door might not be closing properly, or you might have input the wrong settings. Additionally, you might encounter Samsung Microwave temperature control problems due to some problem with the magnetron, the thermo-protector, the cooling fan, or your microwave oven might be in demo mode. 

More than 90 percent of households in the US own a microwave oven and Samsung is a popular choice of brands when it comes to microwave ovens. Sometimes, however, you might encounter a problem with your Samsung Microwave not cooking properly

Components Of A Samsung Microwave 

Source: Samsung

Before we begin discussing the causes of a non-heating microwave oven, let’s take a look at what a Samsung Microwave is composed of:

DoorYou open the door and place your food inside the microwave oven for it to get heated. The door ensures a tight closure so that all the microwaves can be focused on the food rather than getting lost in the surroundings. 
TurntableYou place your food onto the turntable. The turntable spins slowly inside the microwave oven so that the microwaves heat the food from all directions. 
Power CordThe power cord plugs the microwave oven into the power socket and transmits electric current to it. This electricity is then used to generate microwaves. 
Control PanelYou can control the amount of heat required and the duration that the microwave oven will operate through the control panel. It is normally located beside the door. 
TransformerThe voltage supplied by the power supply is too low for the generation of microwaves. The transformer converts this low voltage to high voltage up to 3000 Volts. 
High Voltage DiodeThe current supplied by the power supply is alternating or AC. The magnetron requires direct current or DC for its functioning. This AC to-DC conversion is done by the High Voltage Diode. 
MagnetronThis is the main component of the microwave oven responsible for generating microwaves which will heat the food placed inside the oven.
WaveguideThe microwaves reach the food chamber from the magnetron through waveguides that direct the microwaves toward the food. 
ThermostatThe thermostat is responsible for controlling the temperature of the food chamber. It adjusts the temperature according to the requirements by signaling the magnetron to increase or decrease microwave production. 
Cooling FanThere might be a single or multiple cooling fans in a microwave oven. The cooling fans prevent overheating of the internal components of the microwave oven and allow it to function for longer durations. 
Thermal FuseThe fuse functions to protect the microwave oven from excessive heat.

Causes And Fixes Of Samsung Microwave Not Heating 

Having discussed the components of the Samsung Microwave, let’s get into some of the common causes of your Samsung Microwave not heating:

Power Supply Issues

Power-related issues are a common cause of your Samsung Microwave not cooking properly. These include a power surge which might damage the internal components of the microwave oven, a lack of power which will prevent the effective conversion of electricity to microwaves, or a damaged or worn-out power cord which will cause changes in resistance and thus the amount of electricity delivered to the microwave oven. 

Incomplete Door Closure

It is important that the microwave door closes completely and the sensor within the door is also functioning normally because a microwave will not start its function until the door is completely shut. Thus, issues with the door or its sensor can signal your Samsung Microwave that the door is still open. This will prevent your microwave oven from heating.

Incorrect Settings

If you accidentally put in settings through the control board that do not make sense or are beyond the functional capabilities of your Samsung Microwave, then your microwave will not begin its operation. It might display an error message as well. 

Lack Of Ventilation 

The magnetron can get extremely hot during the production of microwaves. It needs regular cooling so that it can continue to operate without overheating. There are vents installed in your microwave oven through which cooling fans blow cold air onto the magnetron. If these vents get blocked, the cooling of the magnetron would be inhibited leading to ineffective heating of food inside the microwave. 

Non-functioning Cooling Fans

Similar to lack of ventilation, if the cooling fans themselves aren’t working, the magnetron will overheat which will prevent it from functioning properly. 

High-Voltage Diode Not Functioning 

If the high-voltage diode isn’t producing DC for the magnetron, the microwave will not be able to generate microwaves. Thus you will encounter heating problems where your microwave oven might not heat the food at all or might be heating ineffectively.

Magnetron Issues 

In addition to the components necessary for the magnetron to function correctly, the magnetron itself might be having internal issues. This might happen due to overheating, power surge, or physical damage to the microwave oven. 

Broken Thermostat/Thermal Fuse

The thermostat can also be damaged due to power changes, overheating, or physical damage. You will encounter Samsung Microwave temperature control problems since your microwave oven will no longer be able to regulate the temperature of the oven. Consequently, your food might be excessively hot, heated too little, or heated unevenly.

Microwave In Demo Mode

Samsung Microwaves often feature a demo mode that allows you to explore the different functions and features of your microwave. This mode however is only for testing the different functions and does not cause the microwave oven to function. If this mode is accidentally left on, your microwave oven will not perform its function. 

How To Solve Samsung Microwave Heating Issues

Having identified the common causes of Samsung Microwave not heating up, let’s see how you can go about solving each issue. It is important that you exercise caution while fixing your microwave by using gloves, not trying to fix a working microwave, and regularly maintaining your microwave. 

Power Supply Issues

Source: Amazon

If you’re looking to rule out power supply issues, carry out the following steps:

  • Check whether the power cord is properly plugged into the socket. You should also try plugging your microwave oven into a different socket to ensure that the issue is not with the socket itself. 
  • Next inspect the power cord, if it is worn out or damaged you should consider replacing it. 
  • Check the power supply board to see if the power is stable. Do not use your microwave oven if there is a power surge or outage. 
  • Avoid plugging multiple appliances in the same socket so that sufficient current gets delivered to the microwave oven. 

Door-related Issues

Source: YouTube

In order to fix microwave door-related issues you should follow these steps:

  • Check if anything is blocking the door, if there is some dirt or debris it should be cleared.
  • Make sure that the microwave oven is on an even-level surface. 
  • If your microwave door is deformed or damaged you should consider replacing it.
  • Open the housing panel of the microwave door.
  • Separate the door switches from the microwave door keeping a picture of the wiring and connections before separating.
  • Check the door switches using a multimeter.
  • Replace faulty door switches.
  • Connect and reassemble the door housing. 

If your microwave’s door latch is broken, you will find this video by Fix It With Zim quite helpful in the repair process:

Resetting Samsung Microwave

Source: YouTube

Resetting your Samsung Microwave can solve issues where incorrect settings impact the functioning of the microwave. Follow these instructions to reset your samsung microwave:

  • Consider resetting the Samsung microwave clock by using the options, settings, or OK button. Hold down the button for a couple of seconds and then press “9” on the keypad. This will reset the clock settings.
  • If you want to reset the filter light, then you should hold down the “0” button on the keypad.
  • You may also hard reset your microwave oven. Plug out your microwave from the power socket. Leave your microwave unplugged for 15-30 minutes. After that plug in your microwave again and turn it on. 
  • You should use the cooking cycle as a measure of time instead of the kitchen timer.
  • The “keep warm” mode should not be used since it will not heat the food sufficiently, it will just keep it warm.
  • Set the amount of heat required appropriately. 

Cleaning The Microwave And Providing Adequate Ventilation

Source: YouTube

The problem with ventilation should be fixed as follows:

  • Make adequate space for your microwave oven. You should follow the manufacturer’s guidelines in this regard.
  • Check the user’s manual to locate the position of the vents. You should clean these vents using a damp cloth to prevent the accumulation of any dirt or debris. This should be done once every month. 

You may find this video by Samsung Care useful while cleaning your microwave:×522.png

Fixing A Non-Functioning Cooling Fan

Source: Amazon

If you suspect that the cooling fan is the reason for your microwave’s heating issues, follow these steps:

  • Disconnect the microwave oven from power and locate the cooling fan through the user’s manual.
  • Check the wiring and see if the fan rotates by manually rotating it while the microwave is plugged off.
  • If the fan is not working at all or is damaged you should replace it.
  • Reassemble after replacement. has made a helpful video on how you can replace the cooling fan:

High-Voltage Diode Issues

Source: YouTube

If you suspect an issue with the high-voltage diode follow these steps:

  • Disconnect your microwave oven from power and locate the high-voltage diode using the user’s manual.
  • Remove the diode carefully without damaging any other components 
  • Check the integrity of the diode
  • If the diode isn’t working you should consider replacing it.
  • Reassemble after replacement. 

Another great video by will help you with the replacement:×522.png

Checking And Replacing The Magnetron

Source: Amazon

To solve magnetron issues you should follow these steps:

  • After disconnecting your microwave from power, locate the magnetron in your microwave through the user’s manual.
  • Check the integrity of the magnetron through a multimeter.
  • If the magnetron is defective you should consider replacing it. 
  • After replacement, you should reassemble the microwave oven. 

If you are looking to do a Samsung Microwave heating element repair, this video by Appliance Factory & Mattress Kingdom will prove quite helpful:×522.png

Replacing A Blown Thermal Fuse/Thermostat

Source: Amazon

If you are encountering Samsung Microwave temperature control problems carry out the following steps:

  • Disconnect the microwave oven from the power supply.
  • Locate the thermostat from the user’s manual. 
  • Disassemble and separate the thermostat carefully.
  • Check the integrity of the thermostat using a multimeter.
  • Replace a faulty thermostat.
  • Reassemble after replacement.

This video by will help you with the replacement process:×522.png

Switching Off The Demo Mode

Source: YouTube

Put your Microwave out of demo-mode by following these instructions:

  • Press the “Settings”, “Options”, or “Menu” button on your Samsung Microwave.
  • Press the option related to “Demo Mode” on the menu
  • Follow the prompts to switch off the demo mode.
  • Exit the menu and try operating your microwave oven.

You may also encounter similar problems if you use other microwave brands such as LG or Whirlpool.

Troubleshooting Samsung Microwave Heating Issues

The following steps should be followed while troubleshooting Samsung Microwave heating issues:

  • First, check the power supply and the power cord.
  • If the power supply is stable and the cord is also not damaged, check whether the door is closing properly.
  • If there is no issue with the door, check whether the vents are free from dirt and debris and whether the ventilation is proper.
  • Next, check the settings on the microwave oven. Correct any incorrect settings and reset the microwave.
  • If the issue persists, check whether the fuse has blown.
  • If the fuse is intact, check whether the microwave heats the food insufficiently or not at all. 
  • If your microwave isn’t heating the food at all, check the integrity of the high-voltage diode and the magnetron.
  • If your microwave heats the food but isn’t heating enough, then check the integrity of the thermostat and the cooling fan.
  • Don’t forget to switch your microwave oven off from demo mode. 

When To Contact A Professional?

If your issue persists despite going through all the fixes above, then it is best to contact Samsung’s customer support. Also, if you are struggling with replacing damaged components or checking them, you may contact a trained technician. 


How much does a microwave repair cost?

Fixing Samsung Microwave heating function will cost you between $100 to $300. You might be charged extra depending on the degree of the damage and the parts being replaced or repaired. 

How to maintain a microwave oven?

If you’re looking to make your microwave last, you should ensure the following:

  • Clean your microwave thoroughly once a month.
  • Do not leave food sitting inside the microwave for too long.
  • Clean the grease filter regularly.
  • Don’t repair the microwave without any prior training.
  • Do not leave the microwave on during power surges or outages.
  • Operate the microwave according to the recommended guidelines by the manufacturer

Why is my microwave oven showing “PF”? 

PF on the microwave oven means power failure. This may be due to power issues, faulty internal components, or incorrect settings. 

How long do microwave ovens usually last? 

The microwave ovens may be used for 7 to 8 years on average. Depending on the usage and maintenance you might use the microwave oven for several more years. 


  • Raoul Hayes

    Raoul Lobo is a seasoned expert in the realm of home appliances and environmental comfort. As a prominent author at, Raoul's passion and expertise shine through in his insightful articles and guides. With years of hands-on experience, he has become a trusted source for readers seeking advice on pools, washers, dryers, and a wide range of other appliances.

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