Mica burned out in the microwave: what to do, how to replace

Microwave mica is an important element that protects the magnetron and waveguide from high temperatures. The dielectric material also prevents moisture from entering them. Thanks to the mica layer, the emitted microwaves are evenly distributed throughout the chamber.

As the operation of the mica sheet becomes unusable. The first signs that the protective screen has burned out in the microwave are sparking and lack of heat.

Mica – what is it

Mica is a natural dielectric material that transmits radio waves. There are three types: sheet, powder and intumescent.

In its natural state, the mineral crumbles. To use it as a dielectric layer, it has to be applied to an elastic base – the thickness is 0,4-0,5 mm. The color of the mineral is gray-white, indefinite.

Why a microwave protective screen

The “heart” of any microwave oven is a magnetron that generates microwave waves. It communicates with the camera through a waveguide – its output is covered by a special plate that looks like a dense fabric. Located on the right wall. If you press with your finger, the surface is pressed through, behind which there is a rectangular hole in the waveguide.

If your microwave oven sparkles, there is an 80% chance that the mica gasket in it burned out. What is this flexible barrier for? Firstly, thanks to it, the microwaves emitted by the emitter are reflected. Secondly, high-quality heating of products is provided. The gasket is located in the center, on the right or at the bottom.

Why is the waveguide separated from the chamber by mica

The condition for the normal operation of the microwave oven is the cleanliness of the walls of the waveguide. Otherwise, its effectiveness decreases and oxidation occurs. The main purpose of mica plates is to protect the waveguide from grease and other contaminants.

Important! It should be remembered about the plastic lid, which covers the plates with food. If grease or other contamination gets on the protective sheet, an electrical breakdown of the dielectric may occur, due to which it will begin to burn out.

Fat that has fallen on the protective sheet burns under the action of the emitted rays. The plate is destroyed, cracks are formed in it, through which the radiation enters the stove directly. The result is sparking and crackling. Often, in parallel with the overlay, the magnetron cap burns out, the paint burns. If there are signs of burnout – the stove sparks and crackles are heard, turn off the power immediately and take measures to eliminate the malfunction.

Attention! Experts assure: neither peeling paint nor a burnt cap interferes with the operation of the device. But only until the moment when the magnetron antenna does not burn out completely.

What you need to know about frequencies

Many have noticed that mobile phones and Wi-Fi do not function well near the microwave oven. The reason is the coincidence of frequencies. Household appliances use only the values ​​​​allotted to it – among them 2,4 GHz. Waves of this frequency are actively absorbed by water, the screen serves as an insulator of the chamber from the magnetron and waveguide.

Why aren’t there microwaves that don’t interfere with computers? The point is in the instructions of state bodies – it is they who decide at what frequencies to work.

On a note! A microwave oven at a frequency of 2,4 GHz fries a chicken. How does a phone operating at a similar frequency affect if you constantly bring it to your ear? That is why the power of mobile devices is limited.

When to Replace Mica

As the operation progresses, the mica plate, becoming dirty from fat and deformed from moisture, becomes unusable. It can even be colonized by fungi.

The first sign that the wall between the waveguide and the chamber has burned out is loud crackling sound when turned on. Intense sparking begins inside, and electric arcs even appear near the gasket. If you look closely, dark spots are visible on the mica. In the presence of an oval with a diameter of 5-6 mm, the stove begins to “resent”.

The gasket, absorbing fats and aroma molecules, fills with them over time. Further, the material breaks through electricity – a strong spark is observed inside the chamber. To correct the situation, you just need to change the broken protection. How to replace a layer that has become unusable? Sheet mica is sold in specialized stores.

Important! The more thorough and regular care, the longer the protective pad will last. Be sure to clean the inner walls of the chamber from food, wash the smooth parts with weak solutions of detergents, and keep the plate clean.

What to do if there are sparks in the microwave chamber

If sparks are visible in the microwave, there may be several reasons:

• The bottom of the mica sheet burned out. This is the case we are considering.
• Damaged enamel. This can happen due to surface contamination, which provokes sparking.
• Metal utensils. If the cymbals have a metallic finish, sparks will appear.

How to replace mica

If you are convinced that the cause of the crackling and sparks is a burnt gasket, replace it. It is very simple, you do not even need to call the master. If the plate burns out in the microwave, you can replace it yourself. Consider the gasket replacement sequence using the LG model as an example:

• Get a new plate. Where to get it? Search in stores or on the Internet.

Important! When buying a protective screen for a microwave, pay attention to the availability of certificates so that it does not harm your health.

• Remove the heated sheet. It can be fastened in different ways: self-tapping screws, plastic latches. Depends on the microwave model.
• Wash the damaged sheet from dirt – you will need it as a stencil. Cut out the new record with a sharp utility knife. The holes can be drilled with a suitable size drill or pierced with an awl.
• Rub the cut sheet with sandpaper to remove any irregularities.
• Dry it.
• Remove grease and dirt where the mica sheet will be located. Clean the surface thoroughly.
• After removing the magnetron, inspect its protective cap. The damaged part will need to be replaced.
• Burnt areas should be cleaned with sandpaper, peeled enamel should be painted over with a special dye.
• It’s time to put on a new protective screen. Mounting the plate is quite easy, it is usually attached in one of the following ways: – you need to install the sheet in a special pocket, fixed with a screw; – if the plate is held by metal tabs, it must be bent during installation.
• Now check the functionality. But remember: you can turn on the microwave only if there is a moisture-containing product inside – you cannot turn on an empty one. Put, for example, water in a heat-resistant glass.

Is it possible to reheat food without a screen

Owners of microwave ovens are often interested in: is it possible to turn them on without a gasket or do they need to be replaced? The screen is a prerequisite for the operation of the device. If it is out of order, it is forbidden to turn on the stove!

If you want to take a chance, then without a screen, the oven is fully functional. If you are careful to cover the food with a lid, then you can use the stove for a short time until you buy a new plate. The main thing is not to delay the repair so that more expensive parts do not suffer: the cap and the magnetron antenna.

Useful Tips

1. When removing the magnetron, follow the safety instructions: disconnect the device from the power supply, short-circuit it and the capacitor for a while.
2. Mica is fragile, so you need to cut it with a very sharp knife – shoe, wallpaper, stationery.
3. To prevent the accumulation of fat on the walls of the chamber, do not be lazy to clean it by preheating for 10-15 minutes at low power. Then wipe the inner walls with a sponge and detergent that breaks down fat.
4. When heating food, try not to use too large dishes. Suppose a capacious plate does not touch the walls of the chamber, but when the tray moves, it can move out. As a result, touching the walls, the dishes will thin and damage the enamel.

The network often comes across articles where it is recommended to simply turn the mica sheet over. But with this solution, the problem will soon return with additional consequences: the cap and the magnetron antenna will burn out. Then depressurization can occur – the stove will simply stop heating food, and repairs will cost many times more.

Why does the manufacturer use mica, what can replace it

The material must have the following properties:

• do not accumulate electricity;
• be non-toxic;
• do not melt at high temperatures;
• it’s good to pass steam.

If you use a material that does not meet the above requirements, you may be poisoned by harmful substances or get a short circuit. Mica is used mainly because of its cheapness.

You can replace it with another material. Instead, you can use a heat-resistant dielectric – fluoroplast. It is completely smooth, does not absorb fat and moisture. Food grade plastic is a great alternative to mica plates. It is much more reliable and durable, but also more expensive.

Replacing the mica screen is a simple process that you can handle yourself. The main thing is not to ignore the breakdown and replace the plate in time. You can see the details on the video: