How to fix a microwave if it sparks

What to do if the microwave oven is sparking inside

Microwave oven interfaces can be represented by touch buttons and a display. In such a case, in order to detect malfunctions one should check the error code, having previously studied it. The device will self-diagnose and indicate a malfunction or error.

If a pushbutton interface is used, then a mechanical timer and manual mode switches are present. Looking for a breakdown in such a case is easier:

To identify the problem you must test the integrated fuse which is in the control box power supply of the microwave oven.

Use a voltmeter to check the voltage at the transformer input terminal (with the terminals and the connector disconnected).

If after setting the mode and turning on the timer voltage does not appear, then you need to repair the microwave oven control unit. Control box is faulty.

To perform repairs with your own hands microwave oven need to have a set of professional tools, special devices, elements, as well as knowledge of radio engineering. Find on the Internet and download the schematic diagram of a similar unit (as each board contains an individual circuit) or remove the module from the housing yourself and take to the workshop. You can also buy a new control unit and make a replacement.

In conclusion, we can say that microwave oven malfunction appears due to improper use. When you have a microwave oven in your home, you must treat it very carefully and follow all the advice of the manufacturers, both in terms of operation and maintenance.

Malfunction Prevention

Allow the microwave to cool down after prolonged use.

Proper care and operation in accordance with the instructions will prolong the life of the microwave oven:

  • wash the inside surfaces regularly;
  • Use glass and hollow glassware
  • Make sure that foreign objects do not get into the chamber;
  • Use the grill only for baking;
  • Do not close the lids tightly;
  • Do not put large containers that rub against the surface of the chamber when rotating;
  • The foil covering the food must have holes at a distance of more than 2 cm from the edge of the plate;
  • Do not put eggs and nuts for cooking in the chamber.

Washing out the furnace chamber, inspect the enamel. Cracks and chips in the coating open the metal of the housing and cause crackling and arcing.

Place the meat roasting dish in a deep dish so that the fat does not splash on the walls or on the mica cover.

Your microwave oven will last for years with proper care. If it starts to spark, calmly find the cause and repair it yourself.

Preventive measures

To prolong the life of your microwave oven and avoid malfunctions for as long as possible, it is worth following simple recommendations for prevention and proper use

  • Use the correct cookware designed specifically for microwave use;
  • Cover the containers with a lid to prevent fat from condensing on the walls of the cavity;
  • Clean the inside of the appliance after each use to increase the durability of the mica plate and the enamel coating;
  • Do not operate the oven with an empty oven cavity.

It’s also important to keep an eye on the integrity of the wires and plug of the appliance to prevent fires and short circuits.

The main causes of arcing:

Mica plate burned out

In 90% of cases, the causes of arcing inside the microwave oven are due to a burned plate which is usually located on the right, on the inside wall of the oven. It is made of mica and its main function is to allow the microwaves from the emitter (magnetron) to pass through the cavity and protect the magnetron itself from the elements of food being cooked on it.

Generally grease burns through the mica plate. If used in the future, the mica will burn through the metal walls of the cavity and the protective cap of the magnetron and if the malfunction is not corrected in time, the microwave emitter (magnetron) can be destroyed.

  • Check the condition of the mica, it is located in the inner chamber of the microwave oven on the right wall, roughly in the center. If the surface is dirty and burned out, replace the mica plate with a new one (before replacing it, clean the inner chamber of the microwave oven from grease and soot).
  • Remove the magnetron and observe all safety regulations: stop operating the oven; short-circuit the capacitor; short-circuit the magnetron.
  • Check the cap, to see if it is burned. If it is not burnt out (you can see a little spot) put the magnetron back in its place and turn it on.
  • If burned out, replace the cap, refit the magnetron and turn it on. If you didn’t find the cap. change the magnetron.

The rotating disk coupler is burned out

Plastic dome (coupler) located in the bottom of the cavity under the microwave plate may also cause arcing of the microwave oven. Over time, grease and dirt accumulated on this spot cause electrical arcing. Arcing will cause the coupler to heat up and melt.

To correct this malfunction it is necessary to replace the old coupler with a new one of the same kind. Most manufacturers of microwave ovens have typical couplers. Some manufacturers, such as Samsung, Whirlpool, etc., may have substantially different oven mushroom dimensions.

Use of metal cookware

Using metallic dishes and occasionally touching the oven cavity walls. Do not use metal cookware for cooking unless specifically mentioned in the oven manual. Using ceramic dishes decorated with gold or silver powder. Do not use any type of ovenware with metallic finishes.

Damage to the enamel coating in the oven cavity

Sparks can also be caused by damaged enamel coating in the oven cavity. In this case, the enamel coating of the cavity must be restored and a special enamel is used for this purpose. If you paint with other non-specialized products, the vapors of this chemistry can end up in the food.

How to avoid these types of problems. To avoid such malfunctions, the microwave chamber must be kept clean to prevent splashing on the mica plate. Fatty foods should be covered with a special hood or paper towel when cooking. If grease gets on the mica plate, after a while it begins to heat up and spark, which can cause failure of the magnetron (and this is the most expensive part in the microwave) or even burn the inner walls of the chamber of the microwave.

What and Why Sparks, Sparks, and Burning in a Microwave Oven?

What and why sparks, sparkles and burns in a microwave oven? This is a problem we all face sometimes in our daily lives. Let’s try to answer this question in simple language for the average user, not a microwave oven repair specialist.

Let’s explain what happens in a microwave oven when it works.

Microwave oven includes a magnetron. a generator of high frequency electromagnetic waves. When the necessary voltage for its work is applied to it (4,000 volts for the generation and 3 volts for the filament) it emits high frequency vibrations with a wavelength of 12 centimeters through its antenna.

The oscillation frequency is 2.4 gigahertz (2.4 billion times per second) and the wavelength is 12 centimeters. 12 centimeters is the distance over which electromagnetic radiation travels or propagates (as you know from physics, at the speed of light) within the period of one oscillation (the period is 1 / 2.4 billionths of a second). From radio wave theory, if the hole in the body of the microwave oven chamber is larger than ¼ of the wavelength, the radiation will go out (12/4 = 3 centimeters). So, in order for you and me not to be irradiated, the oven chamber must be closed and have no mechanical damage or holes.

Water molecules at this frequency (2.4 gigahertz) are in resonance (begin to vibrate) and the water heats up. This is the basic principle of its operation.

A spark is an electrical discharge or arc between two electrical conductors. Pieces of metal, pieces of metal foil, metallized pictures on dishes, etc., can be electrically conducting. When a conductor is subjected to an alternating electromagnetic field, the electricity induced by this field and the eddy currents appear in it.

When two conductors with different induced electric potentials are separated by a distance smaller than the dielectric separating them (in this case air), an electrical discharge occurs between them (an electric arc). So there are sparks in the chamber of the microwave oven.

Therefore, when using the microwave, gold-plated, silver-plated and metallic tableware should be avoided. When using foil, do not place individual pieces of foil closer than two centimeters to each other and to the chamber walls. The same applies to metal objects.

With electric discharges in the chamber of the microwave oven there is an increased load on the power circuits of electric circuits, which can lead to a breakdown of the household appliance. Do not go without a specialist from your microwave shop or service center. In mild cases, the fuse. a fuse against high currents. will fail. Also, more serious microwave oven malfunctions may occur, such as a magnetron, high voltage diode, or power transformer malfunction.

Repair mica related malfunctions

In order to get rid of the sparking and prevent further failure, you need to perform the following manipulations:

  • Dismantle the old plate, to do this you will need to detach the latches or fasteners, it all depends on the manufacturer;
  • Put this plate on a new one, and use it to cut the mica of the appropriate dimensions, if you have it larger;
  • Also in time of replacement you can check the protective cap on the magnetron itself, and if necessary replace it to avoid further malfunction;
  • Install the new element in place of the old one, and fix it;
  • After all the above, check the microwave oven for proper operation. Never carry out the test with an empty chamber, it may end badly.

Is it possible to operate the microwave without the mica?

Mica for microwave oven is a protective shield for the element behind it. the magnetron, namely its antenna. If used with care, microwave ovens can operate for a short time without the protective screen. To do this, cover all food with special lids.

See also. Microwave repair at home with your own hands

Microwave principle

The main unit of a microwave oven is the magnetron. It generates ultrahigh-frequency radiation that hits the waveguide through the antenna. It distributes waves inside the chamber. Under their influence, the liquid molecules in the food begin to vibrate, heating the food. Therefore, when you turn the chamber on, it must be loaded so that the energy released is absorbed. If it is not, it creates a “standing wave” which causes sparks and breakdowns.

When cooking small amounts of food, put a cup of water in the chamber as well. This way the radiation is better distributed and the food doesn’t dry out.

To protect people from the radiation, the appliance has special protection. So the door must be closed properly and the body must not be mechanically damaged.

The principle of operation of the microwave oven

Before you decide to fix the oven yourself, you should understand the design and construction of the device. A normal microwave oven consists of a magnetron, a capacitor, a transformer, a diode and a fan. In modern models you can find auxiliary elements, such as a grill.


The heart of the microwave is a magnetron, the energy of which is converted into heat. This principle of operation is available due to the anode-supply stabilizer (transformer). The body of the electronic device is placed in a special lamellar radiator, which is constantly blown around by a fan. To prevent the part from overheating, it is equipped with a special thermal fuse. In the first microwave ovens it was the magnetron that was responsible for the lion’s share of the cost. However, over time, the price became affordable, after which mass production began.


Another important element in the construction of the device is a fan that blows air into the cavity, magnetron and grill. The fan allows accumulated air and water vapor to escape. The air circulation in the chamber is accessible through air ducts located inside the microwave oven.

Shielded chamber

Regardless of the cost or model, every heater has a shielded chamber. Metal-protected chamber prevents microwaves from escaping outside. There is a special grid on the glass which is designed to keep the rays inside the microwave. You must also make sure that the door always fits tightly against the body. Never use the device if the door does not close.

Control Box

The control panel is designed to control and maintain the set power of the appliance. These functions can be called basic. advanced models have advanced functionality, which includes: a timer, time and power indicators, auto-menu programs, audible alarms and others.

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Important! Never switch the microwave oven on when it is empty. One of the consequences of neglecting this rule is the failure of the magnetron, which costs as much as half the microwave oven.

Sparks inside the microwave oven: what to do?

Damaged parts of the oven structure can be replaced with your own hands. But in the case of serious problems with the magnetron, diode or transformer, it is better to rely on the help of a professional.

Replacing the waveguide cover

Before we change the plate, let’s talk about the features of the material.

Since the waveguide cover is made of mica sheet, which does not accumulate electricity, is heat resistant, and environmentally friendly, it perfectly meets all necessary requirements. The material is inexpensive and readily available. Also a feature of mica is the ability to reuse the plate if the old sample is not damaged, but only contaminated.

Mica has a porous surface, so it absorbs all the grease that can get on the waveguide, due to which the microwave oven cracks and sparks inside.

If the problem lies only in an unusable mica plate, it is enough to replace it with a new sheet.

microwave, sparks

For the convenience of work, we recommend using the recommendations of the experts:

Microwave oven sparking no problem Hindi

  • A sharp torch and a metal ruler will be handy tools for cutting the plate to the right size;
  • A drill or punch is great for making holes for fasteners;
  • it is better to treat the sharp edges of the cut plate with fine sandpaper;
  • Clean the places where you can see dirt from the removal of the old plate, and only then proceed to install the new part.

Steps to fix the breakage:

  • Unplug the microwave oven.
  • Remove the cover of the waveguide by unscrewing the fixing screw and release it from the grooves.
  • Assess how damaged the waveguide is. If there are no major bumps and scuffs inside, then it was without serious consequences.
  • Remove the furnace housing and disconnect the power terminals by removing the screws that connect the magnetron to the waveguide.
  • Assess the condition of the magnetron. If the cap, covering the antenna, has on its surface light traces from the impact of the arc in the form of small spots, the device can be saved.
  • Sand the surface of the cap with sandpaper. Remove metal dust from its surface with a rag soaked in alcohol. Put the magnetron back in its place and turn on the power.
  • Clean all grease and dirt from the waveguide and emery all blackouts around its window. Remove debris.
  • Put the cover of the waveguide back in its original place. If it is defective, replace it with a new one.
  • Connect the device to the socket.
  • Test the oven. Place a beaker of water inside the heating chamber and start the program to check if it operates correctly. Heat the water until it boils. The function check was successful if the water boils and there is no sparking.

If the surface of the magnetron antenna cap is melted nevertheless, the cap will have to be replaced. It is often removed from a malfunctioning appliance by hand, gently rocking it from side to side. Pliers or pliers should not be used because of the risk of damaging or deforming it.

Ensure the integrity of the antenna before installing a new cap. It is important that the part be set at the same height as before.

microwave, sparks

Synopsis. Since the waveguide is a non-removable part of the appliance, if it is severely damaged, you will have to say goodbye to the device.

Restoring Enamel

Most appliance failures are caused by untimely cleaning of the internal walls from grease deposits. But it is important not only to clean grease deposits, but also to watch for the removal of condensation that forms when the steam is released.

If the beginning of corrosion is not noticed in time and the heater continues to be used, it will soon become unusable. over, foci of unprotected metal have electrical conductivity, that is, microwaves are reflected from the metal and begin to affect the emitter, which will eventually lead to its overheating.

Procedure when traces of corrosion are detected in a small manifestation:

  • Deburring with coarse sandpaper of chips and corrosion spots.
  • Removal of dust and debris.
  • Finely sand the surface and degrease with a solvent.
  • Priming with GF-021, GF-0119, FL-03K, PF-0244 solutions, with the condition of exact repetition of the bottom relief.
  • Smoothing with alkyd putty and grinding with a fine emery cloth.
  • Waiting for complete drying.
  • Application of 2-3 layers of enamel with drying time of at least 20 hours each at 20ºC.
  • After drying the equipment is ready for safe and efficient work.

Important! Pay attention to the composition of used solutions: they must not contain harmful substances. Best for protection and prevention of corrosion are food organic dyes, conductive and acrylic sprays.

In the case of a through hole in the housing, it can be repaired at home with gauze and two-component adhesive.

Do not think that rust under the influence of microwaves emits harmful compounds, and the lack of paint is a danger to the appliance. The slightest deterioration of the enamel reduces the thermal conductivity of the appliance, so heated food takes longer than usual to cook.

microwave, sparks

Help. Microwave ovens with stainless steel heating chambers are the least subject to corrosion and breakdowns. In enameled chambers, however, not only the metal suffers from breakdown, but also the coating.

Preventive measures

The most common cause of damage is drying the oven after washing by turning it on with an empty chamber. In second place is the use of improper cookware.

microwave, sparks

It is not uncommon for problems to occur when operating at high capacity with a small amount of products that have low humidity. The method for solving the problem is simple, it is necessary to place a small container with clean water in the chamber.

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