The main reason that welding suddenly begins to “work” inside the microwave, that is, it begins to spark and crack terribly, is that the plate, which is located inside the chamber itself and which is easy to see with the naked eye, has burned out. What does a prudent owner do in this case? The inefficient person goes to buy a new microwave, which is what manufacturers are counting on. A real man will find a way to fix it.
So, let's begin. We shoot this record right in the camera. It looks like a bank card with a metallic sheen and is scientifically called microwave mica). On many models it is simply attached to the side with an adhesive solution and can be removed very easily. If the model is not the same, we look for a way to remove it (you need a screwdriver and a hammer (just kidding)).
We cut off strips from it on the sides, of such a width to cover the burnt area, usually it is small, and place it on this area. Attach with adhesive tape. That's it - the microwave again works as well as before, without crackling or sparking, and also without loss of power and harm to the body.
And how many people have thrown out microwave ovens precisely because of this problem.
By the way, I haven’t checked it myself, but they say that these plates can be bought for literally pennies and they are sold in almost any market or in repair shops. Well, this is for those who want a new one, and for those who don’t have time, like me, the old one will be repaired.
By the way, it helps to simply seal the place where the burnt plate was with a medical adhesive plaster (i.e., the microwave will work without the “original” plate at all, the main thing is that this place is sealed.
PS I checked the work without a plate and an adhesive plaster at all - it works without a plate and without an adhesive plaster)))
All the best
PPS: Watch another video on this topic:
How a microwave oven works and works
MAGNETRON POWER SUPPLY
The magnetron power supply provides the generation of supply voltages: Anode voltage Ua = 4000 volts A = 300 mA. Filament voltage U = 3.15 volts A = 10 Amperes.
220 volts are supplied through a special control circuit to the primary winding of the power transformer. Next, using a power transformer (which also acts as a stabilizer), the voltage is supplied to the voltage doubling circuit assembled at VD1, C1. Resistance R1 has a rating of 1 to 10 MΩ and is needed to ensure the discharge of capacitor C1 when the stove is turned off. In imported capacitors, the resistor is mounted inside. Safety diode VD2 (fuse diode) serves to protect the transformer from overheating in the event of a short circuit in the magnetron or an excessive increase in the voltage on capacitor C1. Works for breakdown like P2M in Funai TV. When a short circuit occurs, the current in the secondary windings sharply increases, which leads to an increase in the current in the primary windings and the fuse blows. This diode can be neglected i.e. do not install it, but in this case it is necessary to install the fuse strictly according to the nominal value. There have been cases when we received furnaces with a removed fuse diode and a fuse made from a nail. After such a repair, there is no protection left and the poor transformer looks like melted cheese. If you measure the voltage at the cathode of the magnetron it will be exactly -4000 volts (negative), then at the anode relative to the cathode the voltage will be exactly +4000 volts.
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MAGNETRON
1. The metal cap is mounted on a ceramic insulator 2. 3. The outer casing of the magnetron 4. A flange with holes for mounting. 5 Ring magnets serve to distribute the magnetic field. 6. Ceramic cylinder for antenna insulation. 7. The radiator serves for better cooling. 8. Filter box. 9. The connection unit between the magnetron and the power source contains transition capacitors, which together with the chokes form a microwave filter to protect against the penetration of microwave radiation from the magnetron. 10. Power terminals.
A magnetron is a vacuum diode, the anode of which is made in the form of a copper cylinder. I will not go into details of the operation of the magnetron, I will only say that the operating voltage of the magnetron anode ranges from 3800 to 4000 volts. Power from 500 to 850 Watts. Filament voltage is from 3.15 to 6.3 volts. The magnetron is mounted directly on the waveguide. In those furnaces where the manufacturer has a magnetron with a short waveguide, a defect such as a breakdown of the mica gasket can be observed. This happens as a result of contamination of the gasket. Now the price of a mica gasket is in the range of 40-50 rubles. You can cut the gasket using ordinary scissors.
Magnetron defects: 1. When the gasket breaks down, there are often cases when the cap melts. Can be replaced with a cap from another magnetron. 2.Like any lamp, it can lose its emission, as a result of which the energy output is significantly reduced and the cooking time increases. You can increase the service life of the magnetron by adding filament voltage. To do this, you need to wind up 0.5 turns of the filament winding. (in some cases it is possible to extend the service life to 3 years) 4. Breakdown of transition capacitors can be detected using a tester. The breakdown occurs on the magnetron housing. It can be treated by replacing node 9 (see figure).
When replacing the magnetron, you must strictly follow the rules. 1. The antenna diameter and fasteners must exactly match the original. 2. The magnetron must be in close contact with the waveguide. 3. The length of the antenna must exactly match the original. 4. The magnetron power must be the same.
The price of a magnetron on the radio market is from 47 to 70 dollars. It is better to buy magnetrons from companies that will give you the opportunity to exchange them if, for example, the seat does not fit.
HIGH VOLTAGE DIODE
It is a large number of diodes connected in series in one housing. It is impossible to check with a tester. But there is one method that allows you to check a diode with a certain accuracy. If you connect it according to this diagram. The measurement is carried out in two directions, for which the diode must be turned over.
SAFETY PRECAUTIONS WHEN WORKING WITH MICROWAVE OVENS
1. Do not turn on the oven with the door or screen open.
2. Do not make holes in the housing.
3. When replacing the magnetron, be especially careful. Do not leave installation debris in the waveguide. The debris will cause microwave waves to ripple in the waveguide and, as a result, the microwave oven will emit radiation (like a nuclear reactor).
4. Always discharge the capacitance in the magnetron power circuits with a piece of insulated wire (the resistor sometimes fails).
The simplest circuit for detecting microwave radiation.
All information was taken from the Telemaster website
In the comments to the article you can ask questions about the repair of microwave ovens. The question format should be as follows:
- Name, model, year of manufacture
- What have you done already? What did you check? Provide control measurements and other information.
- Are there any elements with visible damage?
- What measuring equipment do you have?
- And other detailed information
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If this information is missing, your comment will likely not pass moderation and will be deleted.
Microwave ovens are complex electrical appliances that can also pose a danger to the user. In normal operating condition, the kitchen unit does not pose a threat, but failure of its functional elements makes further operation unsafe. The difficulty in troubleshooting lies in the fact that one sign of a breakdown can have several causes. If the microwave sparks, this may indicate various problems in the device. Before you begin repairs, you should understand the situation in more detail.
Causes of malfunction
There can be several reasons for the problem – from mechanical damage to overheating of some parts of the microwave. In particular, burnout of the mica diffuser is the most common. Unfortunately, this problem occurs in all types of such furnaces, and it is quite difficult to insure against it. Problems of this kind are not associated with gross malfunction of the device and more often arise due to the poor quality of the element itself. Also, if the microwave sparks when turned on, this may be a sign of damage to the internal surfaces in the chamber itself. The fact is that the inside of microwave ovens is treated with special enamel coatings. Deformation of this layer usually occurs as a result of the use of metal utensils. That is, breakdowns of this kind can be prevented if the basic rules for operating an electrical appliance are followed. By the way, it is undesirable to use ceramic dishes with metallized coatings for heating in the microwave.
Why you shouldn’t do zeroing and DSUP in the TN-C system
So, we have come to the point that grounding is necessary. However, in houses built before the mid-90s, the TN-C system is implemented. This means that the conductor of the working solidly grounded zero also performs the protective function of PE (grounding). Therefore, it is called PEN (protective zero PE + working zero N) and is not divided along its entire length from the transformer substation to the floor switchboard. Therefore, there is no grounding in the floor panel, there is only a PEN bus. Connecting the protective (third) conductor of the apartment electrical wiring to the PEN in the floor panel is called “grounding”.
I don’t want to throw too much water on this matter, it’s worth taking a look at the pictures below. The principle demonstrates the consequences of damage to the PEN conductor. The pictures show grounding in the junction box (I strongly do not recommend doing this), but they demonstrate the essence - safety will not be particularly improved by grounding in the switchboard.
It is worth noting that the burning of the zero at the transformer substation, which electricians are afraid of, is not the only reason to be afraid of zeroing. Elementary contact between a floor electrical panel and a conductive PEN conductor is very unreliable, given decades of operation.
The photo below is an example of an unreliable connection, just think: if you zero electrical appliances in the bathroom to such a contact, as soon as it warms up or oxidizes a little more, the housings of all working, “zeroed” appliances will be under a voltage of 380 volts!
After all, this working zero provides a voltage of 220 volts between one of the three phases and the PEN bus, when the contact with it is destroyed on the floor panel, then two apartments (or three) are connected in series to two phases (or three).
I hope I have given enough arguments for the reader to refuse nullification. It’s sad, but you shouldn’t count on high-quality grounding until the home energy system is reconstructed. Until this moment, it is better to live without grounding at all.
Some inquisitive minds may think: What if you make a grounding and, in addition, build a DSUP in the bathroom? After all, even if a phase appears on the protective conductor, all metal objects in the bathroom will also have phase voltage and there will be no conditions for current to flow through the body!
Indeed, if all conductive objects, including the bathroom floor fittings, operate at the same potential, the person there will be safe... Until he crosses the potential equalization zone. Moreover, in such a situation the neighbors will certainly suffer. Therefore, it is strictly prohibited to perform potential equalization in an apartment using the TN-C system.
Naturally, water pipes, heating pipes, or fittings protruding from the wall also cannot be used for grounding.
This is not possible, it is prohibited - so what to do if there is no grounding in the apartment?
What exactly sparks?
To understand the causes of this problem, you need to understand the very nature of sparking. So, if the microwave sparks and crackles, this means that there is an interaction process between two electrical conductors inside. In other words, conditions were created for the formation of an electrical discharge or arc. Such phenomena can be accompanied not only by sparking and crackling, but also by light effects, which looks even more frightening.
What elements in this case provoked the sparking? These may well be metal elements that ended up in the chamber with the dishes. Again, it doesn't have to be all metal utensils. If a microwave with a ceramic plate sparks, it may be due to pieces of foil. Moreover, a charge does not always occur even if there are full-fledged metal parts in the chamber. To activate such processes, there must be appropriate power, which will be enough to overcome the barrier in the form of an air dielectric.
The washing machine must be grounded
Any manufacturer of washing machines, when designing their device, focuses on the fact that all electrical networks must be grounded. That is, your outlet must have three wires: phase, neutral, ground. In fact, 90% of houses in Russia do not have grounding. Unfortunately, according to USSR standards, grounding was not necessary.
In modern construction, this defect was taken into account “on paper”, but in fact, there may also be no grounding. No, of course you can find a ground wire in the sockets, but where it goes next and whether the grounding is really properly organized in the house is a big question. In our practice, we have encountered hotels that were made according to all modern standards, and if you go down to the basement of this building, you can see all the grounding wires twisted into one knot, which simply dangle and do not perform their function.
So what should we do? The first thing you need to find out is whether you have grounding in your home. This information should be provided to you by the Housing Office. If there is grounding in your house, then you will need to find the corresponding wire in the panel. In this case, your problem can be solved by laying a new three-wire wiring, where all sockets will be grounded.
Never use water pipes or heating pipes as grounding. In this case, if the device breaks through the body, you can harm the life and health of not only yourself, but also your neighbors.
Of course, the issue of grounding is very difficult to solve, even if your house has it. After all, changing the wiring is not so easy, so we will have to get out of the situation in other ways.
Can I use a sparkling stove?
The answer to this question depends on the condition of the microwave oven and its components. The mere fact of sparking does not always indicate damage to the same diffuser or enamel coating. Another thing is that the appearance of sparks should be a reason for a comprehensive inspection of the device. That is, if the cause of this phenomenon was the very presence of a metal element in the chamber, then further operation is quite acceptable provided that the functional contents of the device are intact. But in any case, it is important to stop the heating process if the microwave sparks. What to do in such situations? First of all, turn off the device through the control system. Next, the power supply is turned off. After this, the working elements are checked, among which the most important will be the magnetron - the most expensive and critical part of the microwave.
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Other interesting questions and answers
What to do when you get an electric shock from tap water?
Guest2
If you do not want to suffer electric shocks from the faucet, you will have to do the following:
- Replace all sockets in the kitchen, bathroom and toilet with special models with a moisture protection class of at least IP44 or IP54. They will protect you from accidental breakdown of the socket body.
- Examine the wiring with an ohmmeter or a hidden break detector. Increased resistance in the area or a detector signal will indicate the location of the breakdown.
- Replace all problem areas of the wiring, or even better, replace the entire line leading into the bathtub, kitchen or toilet, using a special, moisture-resistant cable.
- Call a technician and ask to replace the heating element on the washing machine, dishwasher, and also on the boiler. Unless, of course, the source of the problem is water heating electrical appliances.
Vladimir1
The reason that a stream of water produces an electric current may be the lack of grounding on a washing machine, water heater or other electrical appliance that is connected to an outlet in the bathroom/kitchen or is located next to it. This may also mean that the wiring is faulty, a wire is twisted somewhere, or the wires are damaged. It happens that your neighbors have errors in the grounding of the water heating system, and an electric current is generated from the water from your tap. If you are sure that the problem is not in your apartment, then you need to look for neighbors who share a common riser to solve the problem. If in your bathroom or kitchen all the sockets and all the wiring are adapted to humidity, there are no problems with grounding and there is no damage to the electrical wiring and the appliances themselves, then contact the Housing Office/DUK to check the neighboring apartments for malfunctions. To determine your problem, call a specialist; it is better not to deal with electricity yourself, and this should be done as soon as possible. The electrician will conduct diagnostics and, if necessary, replace problem areas of wiring, switches and sockets, and indicate malfunctions of the water heating system and electrical appliances. It's good to have an electrician assigned to your home who may already be familiar with the problem if it's not a one-off problem. In addition, prices for services from housing office electricians are lower than from specialists from third-party companies. Natalya K.3
Why does tap water produce an electric current when the washing machine is turned on?
There are no intersections, they just stand next to each other. Leaks too. It hits little by little, barely noticeable on small wounds on the hands.
iris3
Either there is bad grounding here or there. In addition, there is an insulation failure somewhere. Let’s say that in a washing machine the insulation in some place is not good enough and a “bridge” has formed, through which electricity flows to the body. If the grounding is connected incorrectly or is missing, but there is a small voltage on the case. Water pipes, on the contrary, are well grounded and the resulting current goes into the ground. In this case, if you hold the washing machine with one hand and the water pipe with the other, then you are closing the electrical circuit. The wounds on the hand, as the most sensitive place, feel a small current. This can be dangerous because in a damp room the effect of the current is only enhanced due to worse insulation. You need to take a device (for example an ammeter) and check where the problem is coming from. Of course, it may turn out that everything is fine with your washing machine, but a small current flows from the side of the water supply system through some faulty electrical appliance.
Sveta17082
The water from the tap gives an electric shock... but only to me! Why?
Everything was fine before, but now... I’ll take a piss, wash normally, and two seconds before turning off the faucet shocks me! I turn off the tap and it goes crazy again! And the battery is hanging there. And after that, if I turn on the sink in the bathroom or kitchen for half an hour, the water flows out there. And only me! Grandma laughs and says that you need to sit on the phone less... But if it were the phone, it would ring immediately and constantly like... Alena .4
So some smart guy made a grounding connection to the water pipe. Seryozha3
Checking the magnetron
This operation is performed by electrically ringing the contacts of the part. The contacts of the high-voltage transformer are connected to the magnetron - they should be checked for functionality. Masters usually examine such areas for the presence of resistance, and the electromagnetic responsiveness of the device body is also assessed. If there is activity, then the magnetron is fine and does not need to be replaced. But even with a working magnetron, you can observe how the microwave sparks. What to do in such cases? You should begin to inspect the mica diffuser and the condition of the enamel coating.
Wrong methods to solve the problem
If you decide to deal with the problem yourself, you need to understand what actions are not advisable to take. When “studying” forums, along with competent advice, you can come across incorrect recommendations from “would-be masters”
So, do not take into account and use the following troubleshooting methods:
- If there is no grounding, you can simply insert the plug into the socket, turning the plug over, and also cover the floors in your visit with a rubber mat. This method, of course, can stop single impacts, but it will not solve the problem. Ultimately, the user may still be electrocuted.
- Stop the washing machine's surge protector. This element is designed specifically to redirect the electrical charge to the body of the machine. Common people believe that turning it off will completely protect against electric shock when touching equipment. This opinion is wrong; the risk will decrease only slightly.
- Connect the grounding conductor from the automatic machine to a pipe or radiator. Such actions are very dangerous and can result in severe electric shock. Experts categorically do not recommend using this method.
- Remove the isolated PE cable from the shield. Remember, you cannot install a separate grounding conductor and plug the equipment into an outlet without a ground. The correct solution would be to remove the three-wire wire from the distributor and connect a special, safe socket to the cable.
By finding out the reason why the washing machine drum periodically shocks you, you can eliminate such a dangerous nuisance
It is important to carry out repairs consciously, observing all safety regulations
Mica diffuser repair
The microwave diffuser is a mica plate which, if damaged or excessively dirty, can cause sparking. This is a small part that can be repaired on its own if the microwave sparks when turned on. The repair will consist of updating this component. It is necessary to purchase a diffuser that matches the characteristics at the service center of the manufacturer of a specific model or on the radio market and replace the old plate with it. Moreover, sometimes experts recommend not dismantling the old mica plate, but only installing a new element and first cleaning the installation site.
Can the device be used?
When the washing machine “pinches” slightly when touching the body, many users decide not to contact a technician to fix the problem, hoping that nothing serious will happen. It is very important to understand that such behavior is unacceptable. Continued use may result in serious injury or damage to the washing machine itself. All manufacturers strictly prohibit the use of their products in such situations. It is worth remembering that a small breakdown today can lead to huge problems tomorrow.
Restoring the enamel coating
The formation of sparks can also result from mechanical damage to the enamel-treated chamber walls. The latter is used not only to form dielectric insulation, but also to maintain surface cleanliness. During operation, it is quite possible that this layer may be damaged by the edges of the dishes or as a result of careless movements with food. If after such manipulations the microwave sparks, it means that the insulating coating has been damaged and needs to be restored. Damaged areas are repaired using specialized environmental compounds. The working surface is first cleaned, after which new enamel is applied in accordance with the instructions.
How to avoid microwave sparking?
It has already been noted that sparking occurs either due to low-quality components or due to violations of operating rules. To minimize such risks, other recommendations for using such ovens should also be followed. For example, you should not heat food without covering it with a special lid - splashing greasy particles, for example, can contribute to the same damage to the enamel. The microwave often sparks due to excessive contamination of the mica plate itself. It may be intact, but dirty. In this case, it is not necessary to purchase a new element - it is enough to carry out timely care of the mica surface.
What can't you do?
People ignorant of electrical engineering often look for advice on the Internet. Some of them are absurd and even dangerous. Here are not the most useful recommendations:
- Disable the surge protector. The danger of defeat is not eliminated.
- Connect the ground wire to the heating radiator. This is very bad advice and increases the likelihood of failure.
To ensure that your washing machine is a source of comfort and not electricity, take its connections seriously. By ensuring reliable grounding of household appliances and installing a protective device, you will eliminate the possibility of damage.
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