How to Change the Transformer of a Microwave

Jul 29, 2023, 11:27am

The transformer increases the supply voltage of the microwave. In this device, the magnetron produces the waves that heat the food. It needs a very high voltage: the 230 volts from the mains are therefore not enough. The transformer makes it possible to pass this voltage from 230 volts to more than 2000 volts.

Its operation is based on the principle of electromagnetic energy, with coils and turns. If it is a little damaged it may no longer work.

In this case, the following failures are possible:

  • The microwave does not start
  • The microwave makes noise
  • The microwave causes the electrical installation to trip

The transformer is located behind the control panel, below the magnetron. You will have to remove the lid of the microwave to access it.

A microwave is a household appliance that has made our lives significantly easier by enabling us to heat food quickly. It operates using a complex system of components, one of the most crucial being the transformer. The transformer in a microwave steps up the regular household electricity supply to the high voltage needed by the magnetron to generate microwaves. Over time, like any electronic component, a microwave transformer can wear down or break, necessitating a replacement. This article will guide you through the process of changing a microwave’s transformer.

How to Change the Transformer of a Microwave


Working with microwave transformers can be dangerous due to the high voltage they handle. This guide is for individuals who have a good understanding of electronic appliances. If you do not have experience with electrical repairs, you should hire a professional technician to carry out this task.

Tools You Will Need:

  1. Screwdriver (Phillips and flat-head)
  2. A new microwave transformer
  3. Pliers
  4. Wire cutter
  5. Wire stripper
  6. Electrical tape or wire nuts
  7. Multimeter (optional)

Step-by-Step Procedure

1. Unplug the Microwave

Safety should always be your first priority. Unplug the microwave from the power source before starting.

2. Remove the Microwave’s Outer Casing

Using a screwdriver, remove the screws that secure the outer casing of the microwave. Lift or slide off the casing and set it aside. Keep the screws in a safe place for later use.

3. Locate the Transformer

The transformer is usually a large, metal, rectangular component located at the bottom or side of the microwave.

4. Check the Transformer

If you suspect the transformer is faulty, you can use a multimeter to test it. A functioning transformer will display a reading of continuity. If the transformer doesn’t have continuity, it needs replacement.

5. Remove the Old Transformer

Before removing the transformer, make sure you have identified and marked the wires connected to it. Then, disconnect these wires. The transformer is usually held in place with screws or bolts. Remove these, and you should be able to lift out the transformer. Be careful; transformers are heavy.

6. Install the New Transformer

Position the new transformer in place, ensuring it sits securely. Reconnect the wires as they were connected to the old transformer, making sure the connections are firm. If you need to, use a wire stripper to expose fresh wire, twist the wires together, and secure them with wire nuts or electrical tape. Replace the screws or bolts to secure the transformer.

How to Change the Transformer of a Microwave

7. Reassemble the Microwave

Replace the outer casing of the microwave and secure it with the screws you set aside earlier.

8. Test the Microwave

Once everything is back in place, plug in the microwave and try to operate it. If it works, you’ve successfully replaced the transformer. If not, or if there’s an issue, consult a professional technician.

Remember, microwaves are high-voltage appliances, and mishandling can lead to electric shocks or other accidents. Unless you’re confident in your abilities to handle such repairs, it’s always recommended to seek professional help when changing a microwave’s transformer.