How to demagnetize a TV at home

Many owners of outdated TV models are wondering: how can you demagnetize a TV at home? People encounter this problem when the device starts to malfunction, showing a distorted picture. This problem is inherent in most cathode ray tube devices and is called “magnetization.”

Why is this happening

The main reason why a kinescope becomes magnetized is the prolonged presence of electronic devices in close proximity to it. In modern homes, this situation is not uncommon: microwave ovens, computers and telephones are present in almost every apartment. It’s not uncommon for a TV to be placed on a microwave without thinking about whether it’s possible to do this? If your device has suffered from regular exposure to an electromagnetic field, do not rush to take it to the workshop. You can solve the problem yourself. Depending on how strongly magnetized your TV is, you may be able to fix it using one of two options:

activate the built-in magnetization protection;
use a device called a throttle.

Important: never use a permanent magnet to demagnetize the picture tube.

Screwdriver magnetizers

A screwdriver with a magnetic tip is, of course, good, but in some situations it can, on the contrary, interfere or even cause harm. For example, when working with electronics, a magnet can cause serious and irreparable damage to some parts.

And constantly juggling screwdrivers is quite stupid and inconvenient. Therefore, most craftsmen who often have to use a screwdriver use a special device, a magnetizer. With it you can quickly magnetize and demagnetize the tool without much manipulation.

Previously, such a service could be performed in workshops, but now, with the arrival of this device, there is no longer a question of how to magnetize a screwdriver at home.

Magnetizers are simple in design and use, which can change the corresponding parameter of metal objects. A huge advantage of the device is that it does not require additional connection to the network or recharging. And the small dimensions allow you to always have such a useful thing with you. And if we consider the design itself, the magnetizer consists of:

polymer case with slots for metal objects;

a set of magnets of different polarities.

Each of these holes is responsible for one or another function, magnetization, demagnetization. Usually, the slots are labeled, but even otherwise, you can very quickly check the parameters of each compartment.

The principle of operation is incredibly simple: place the object in the desired hole, wait a little. These devices differ in the size of the instrument itself and the size of the incision. The second parameter depends on how large the object needs to be magnetized.

How to diagnose the magnetization of a kinescope

Magnetization of the CRT causes distortion of the image on the TV screen. But picture distortion is possible not only due to the presence of screen magnetization. It is first necessary to clarify the reason.

CRT TVs from most well-known manufacturers (Philips, LG, Sony, Samsung, etc.) are checked for the mask magnetization effect using the “Blue Screen” settings option. The diagnostic procedure is as follows:

Before carrying out the test, the external antenna should be disconnected;
Turn on the TV receiver and launch the “Blue Screen” mode through the settings menu.

To check magnetization, you should activate “Blue Screen” in the settings

The appearance of multi-colored stains and spots on the blue screen indicates the magnetization of the kinescope.

Useful tips

To prevent the TV from being magnetized, you should carefully study the recommendations of experts presented below. To avoid problems such as magnetization, it is necessary to operate the equipment correctly. This requires:

disable it correctly: via a button;
After work, give the equipment time to rest.

If a posistor has failed and it is not possible to replace it with a new one, then this element can be removed from the board, and you will need to use a soldering iron. However, this will only cause a short-term demagnetization effect - after a while the screen will return to its original state.

In modern TVs, magnetization is checked by selecting the “Blue Screen” function.

To do this, you need to go to the TV menu and find the item of the same name. If this section in the menu is enabled, then if there is no antenna or if the signal is of poor quality, the screen will turn blue.

So, select the “Blue Screen” function, turn off the antenna - a blue screen appears. At the same time, we pay attention to the quality of the blue tint. If there are spots of different colors on the display, this means that the screen is magnetized. It is worth noting that modern LCD monitors have a special degaussing function, which is located in the equipment menu . For this reason, using it will not be difficult.

See below for how to demagnetize a kinescope.

Activating built-in protection

Each CRT TV has built-in protection against screen magnetization - the so-called demagnetization loop. To put it into action, just turn off the device for a while and let the loop do its job.

You need to know that this loop starts working only when the device is disconnected from the power supply. The thing is that when the power is turned on, voltage is supplied to the posistor continuously, and it cannot limit the supply of energy to the demagnetization loop. In this case, the demagnetization system remains inactive. Experts recommend periodically disconnecting the TV from the electrical network to prevent possible problems with the picture tube.

Vladimirs Vorohobovs

Many irresponsible residents take advantage of this. installing magnets near their meters and thus stealing water.. However, now there is an inexpensive seal that can be put on an already installed water or gas meter. Like a regular seal, it has its own unique number or letter code, which can be recorded in a journal and thereby verify that the seal has not been replaced. Installing such a seal on a meter does not require complex skills.

I didn’t find a single loss, I also found a court - a fine against them for tax evasion.

In general, to give more information against scammers:

1) We meet with them at the office to make a claim (in my case, I didn’t even find an office - at the specified address there is a nine-story residential building). There are no workers. The manager, a 24-year-old boy, refused to meet with me at a time convenient for him - he sent a written complaint about poor-quality measurements. I refused to pay the cost of measurements - 350 rubles for each meter (I have 4 of them and they all showed the same value, like other cases - very interesting, isn’t it? Do they have a scale with one value?) , because does not want to take repeated measurements in my presence and provide the documents required by law.

2) We look carefully at the measurement report - there are no signatures of the measurer (strange, the one who measured refused to sign the document...) and members of the commission. Only two negotiating bosses. Moreover, there was no commission - it stood on the site and did not enter the apartment. What then did the head of the HOA sign if she was not present during the measurements?

3) We read the laws and immediately forget about this piece of paper... We ask them for an accreditation certificate (costs 200 thousand, requires an office, equipment and at least two certified specialists) and a certified methodology (issued only by the Ulyanovsk Metrology Center)

4) We write to the manufacturer with a request for an independent examination and receive from them a colorful color letter with three seals and the signature of the deputy director that there are no norms, no standards, no GOSTs, and no internal specifications to refute or confirm the measurement result . No one has ever measured them and no one is going to do so. (Well, Ulyanovsk is ahead of the rest! And why is it that only we have come up with the idea of measuring something, but not Moscow?))

5) For insurance, we call the metrology center and present to the chairman of the HOA the specified certificates of verification of the certified (and ONLY

in Ulyanovsk an organization) that has the right to check water meters (it turns out that not everyone who gets there has the right to check them...)

You can stop the water meter with some tricky manipulations with a neodymium magnet. To do this, use a magnet in the immediate vicinity of the counter to find the point where it stops completely. This can be the front side, the side surface of the meter, and less often the back wall of the device. The reader performs all manipulations experimentally at his own risk. This information is taken from open sources on the Internet, is provided for informational purposes only, and does not oblige you or push you to anything.

Replacing a failed posistor

Turning off the device for 10-15 minutes does not always help get rid of the problem. There are two ways to correct the situation caused by strong magnetization of the CRT screen:

replacing a failed posistor - an electronic component in the standard demagnetization loop circuit;
demagnetization using a choke.

The reason for screen magnetization is often a malfunctioning posistor. The situation is corrected by replacing the failed electronic component of the circuit. Purchase a part suitable for resistance at a radio store. If you know how to read an electronic circuit and have the skills to work with a soldering iron, removing a used posistor and soldering a new element in its place will not take much time.

Possible cause of the malfunction is a failed posistor

If for some reason a working posistor cannot be found, then to temporarily solve the problem it is enough to unsolder the faulty element. The broadcast of the picture will be restored without color distortion for some time. After which the problem will appear again.

After replacing the posistor, you should turn the TV on and off several times at intervals of 15-20 minutes. When the current supply is turned off, the posistor cools down, its resistance decreases, thereby activating the demagnetization loop. For the complete disappearance of color spots on the screen, 5-7 cycles of turning the device on/off are required.

If the built-in mechanism cannot cope with the complete elimination of image distortion, then you can demagnetize the CRT screen using a choke.

Reasons for magnetization

The shadow mask of a cathode ray tube (hereinafter referred to as CRT or kinescope) is a structural element of a kinescope made in the form of a raster grid. As a rule, it is made of invar (an alloy of iron and nickel), which has a small coefficient of thermal expansion.

The shadow mask in the CRT design ensures that electron beams of blue, green and red colors are projected onto the phosphor layer . While the TV is operating, the electromagnetic field created by its components (transformer, speakers, etc.) magnetizes the mask, which is why the electron beams may not converge correctly. This in turn contributes to the appearance of distortions on the screen.

To avoid this effect, picture tubes are equipped with a special device that should remove magnetization from the shadow mask. It includes a kinescope demagnetization loop and a posistor.

Reference! A posistor is a thermistor whose resistance increases when heated. They are also called PTC thermistors (PTS - Positive Temperature Coefficient, from English - positive resistance coefficient).

Defects caused by strong magnetization of the mask do not indicate failure of the kinescope and can be easily eliminated by the TV owner with his own hands. It should be remembered that the functional unit pre-installed in the television receiver, which prevents the magnetization of the mask, is activated only when the TV is turned off.

Experts divide the reasons that lead to magnetization of the CRT mask into two groups:

defects that appear as a result of long-term use of the TV and failure of parts of the demagnetization system;
malfunctions caused by external factors.

Demagnetization using a choke

To carry out the procedure, a factory device is recommended; as an option, a homemade inductor coil is suitable.

Factory choke for demagnetizing the kinescope

You need to act in the following order.

Unplug and remove electrical appliances close to the TV.
Turn on the TV and let it run for 10 minutes to warm up.
At a distance of 2 meters, set the throttle parallel to the screen and turn it on.
Slowly bring the device closer to the TV screen, making circular movements with it, gradually reducing the diameter of rotation.
Directly at the TV, you need to draw the throttle around the perimeter of the screen several times for 3-5 seconds.
Continuing to draw circles, you should move away from the TV to your original place.
Turn the coil perpendicular to the TV screen and turn off the device.

The process must be carried out very quickly (15-20 seconds) to avoid overheating of the inductor, without being distracted by the sounds and color distortions made by the TV.

Important! The described solution to the problem is only suitable for TVs with a cathode ray tube. It will not be possible to eliminate stains on LCD TVs using a choke, since the reasons for their occurrence are completely different.

Internal structure of the element

A resistor changes its resistance with heating, just like a posistor. How to check the first element? This one is simple. The resistor values fluctuate within insignificant limits. A posistor is capable of completely blocking the current passing through it, just like a themistor. Only the latter exhibits an inverse dependence on temperature.

To know how to check the serviceability of a posistor, you should determine its main operating characteristics. These include:

nominal resistance at normal ambient temperature (usually 20-25 degrees);
The switching resistance is determined at the point of the resistance versus temperature characteristic when the first parameter increases by 2 times compared to the nominal value;
the maximum voltage that the element can withstand without failure;
current load values: rated, switching, maximum possible and stalling; For testing, these parameters are important only if the posistor will be used in high-precision circuits.

How to make a choke at home

You can assemble an electric magnet at home using an electric wire with a plug, an iron arc and a winding.

Homemade choke

Take an iron arc and connect it to the electrical network by connecting it to a 220V wire. Isolate the resulting device and plug it into the power supply. The sequence of actions is no different from the process of demagnetization with a special choke.

If you followed the instructions in the article exactly, but your device for watching television channels still shows a poor-quality image or does not show it at all, a possible reason is a shift in the shadow mask of the kinescope. This malfunction cannot be repaired, and the only solution to the problem is to buy a new picture tube or TV. Now there are many models on the market, and in order not to make a mistake when purchasing, you need to know the parameters for choosing a TV. The optimal solution would be to choose a modern TV with Smart TV running on LED technology.

Buy a neodymium magnet for a water meter in Ukraine

If you decide to use magnets to stop the water meter, follow the safety rules - these are not toys. Their strength is such that they can harm children, and large ones can harm adults. The information on the site is presented for informational purposes only and is not a guide to action; the site administration does not bear any responsibility for your actions! Using magnets to stop meters is illegal. A magnetic washer on a water meter is the safest and most effective way to save money.

Another question has arisen.

I assumed that it was possible to remove the magnetization with a magnetic loop, or whatever it’s called, the one with which picture tubes were demagnetized before.

Steps

"soldering gun"

"Plugpack converter"

"hard drill"

If you are still having problems, check the area near your monitor for magnetic sources such as unshielded speakers.
LCD and plasma monitors never need to be demagnetized because they are not CRT-based monitors.
Some monitors can be degaussed by holding down both the brightness and contrast buttons located on the front of the monitor.
You can degauss an old monitor (or even a CRT TV) if you have a new monitor (with degaussing) nearby. Place the old monitor directly in front of the new one (as close as possible, facing each other; and they should both be turned on). Then degauss the new monitor. You will see that they will both be demagnetized!