How to demagnetize a kinescope at home. How does a neodymium magnet act on a TV?

Almost every inhabitant of this planet has a favorite show, series or movie. No matter how much we want it, the means for watching a TV program sometimes fails. It often happens that cathode ray tube (CRT) TVs begin to change colors in the picture image: your TV may have green or red stripes on the screen along the edges of the image. Demagnetizing the TV screen will help get rid of this unpleasant phenomenon.

You will need

A special device (choke) for demagnetizing picture tubes.

Sponsored by P&G Articles on the topic "How to demagnetize a TV" How to demagnetize a TV's kinescope How to restore a kinescope How to connect sound to a TV

Instructions

As a rule, it is possible for everyone to determine the malfunction of the monitor, namely, to detect the appearance of green stripes. There may be two reasons:
- magnetization of the TV screen (kinescope);
- shift of the kinescope mask.

Magnetization of the TV screen occurs due to the fact that there may be electrical household appliances near the TV that have their own magnetic force. The opposition of these forces causes magnetization. If you look at some electrical appliances in the store household appliances, then the instruction manual or price tag indicates the item shielded protection (protection method). For many audio device models, this option is required. For example, audio speakers for a computer without shielding the speakers cause a rapid loss of performance near a standing monitor. The shift of the picture tube mask cannot be corrected, therefore it is estimated at the price of a new monitor (picture tube).

There are 2 ways to correct TV magnetization: +

When low magnetization occurs, the TV provides protection from such a factor affecting the image on the screen (demagnetization loop). It is enough to turn off the TV and leave it in a standby (rest) state from several to several hours (depending on the TV model).

If the “demagnetization loop” does not work, then you need to purchase, or better yet, borrow a special choke that demagnetizes the picture tube of your TV. When demagnetizing with this device, you must follow the exact sequence of actions, which are described in detail in the operating instructions. The principle of operation of the SS choke can also be told to you by a friend from whom you may borrow this device.

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Magnetized kinescope

The image showed colored spots, stripes, and incorrect colors, all these are signs that the kinescope mask has become magnetized. You can call a specialist, but this article is about how to demagnetize a kinescope yourself.

There are two reasons for the magnetization of the kinescope: a malfunction in the TV itself or it was exposed to external magnetic field, for example from a nearby speaker system, a permanent magnet brought to the TV, as well as a magnetic field from devices such as a transformer stabilizer or uninterruptible power supply.

There are two options to demagnetize the TV picture tube:

• with a slight magnetization, the TV can handle it on its own; for this it has a demagnetization system. You just need to turn off the TV from the network and wait 10 - 15 minutes to turn it on again. If the image improves, the procedure can be repeated.
• If it was not possible to demagnetize, then you need to buy, or better borrow from friends, a choke to demagnetize the kinescope. If you couldn’t find it, then it doesn’t matter, you can make it yourself.

The principle on which demagnetization is based is a smoothly disappearing alternating magnetic field. Do not make any sudden movements during operation, otherwise this will lead to re-magnetization.

Once upon a time I used a factory throttle, borrowed it from a friend. He demagnetized not so much television picture tubes as tape recorders, and this is what he looked like.

Today's TVs cope better with magnetization, I even forgot when I had to use the throttle.
In order to make a choke for demagnetization, we take a 100 mm mandrel and wind it 850 - 900 turns with PEL-2 wire, 0.15 mm in diameter, and completely insulate it insulating tape. To turn it on and off, attach a button and a 220 V power cord to the device.

To demagnetize the kinescope, perform the following steps:

1. Turn on the TV and let it warm up for 10 minutes;
2. Position yourself at a distance of at least 2 meters, turn on the throttle and, first, with large circular movements, and then less and less without stopping the rotation, slowly approach the kinescope for 3 - 5 seconds. In this case, severe color distortions will begin to appear in the image;
3. After this, without stopping the rotation, we also slowly move away old place and turn off the throttle. After such an operation, the distortions should disappear. If not, then repeat the procedure again.

Remember: Don't keep the throttle on for a long time to prevent it from heating up. The entire operation should take about 30 seconds.

If you are too lazy to wind the throttle, then you can use an almost ready-made one, this is a coil magnetic starter. It can be either cored or without, with a voltage of 220 - 380 volts.

How larger size all the better. Since its dimensions are small, the uniformity of the magnetic field will accordingly be worse. In the case of using a core, the field becomes stronger.

Remember - never demagnetize the TV picture tube permanent magnet, this will only make the situation worse.

CRT TVs have one feature. Over time, the TV screen may magnetize and start distorting color scheme. Also, during magnetization, dark spots appear on the screen. This may happen due to not correct operation TV, or a random gift electrical appliances to the TV. To protect yourself from such incidents, follow the rules for installing a CRT TV in your home. Don't put it close to others household appliances, do not use other equipment near the TV.

If the TV is still magnetized, then do not rush to call a technician. You can try to demagnetize it yourself

How to demagnetize a TV screen

The first method is the easiest - TVs are equipped automatic demagnetization system. To demagnetize your TV screen, simply unplug it for 20-30 minutes and turn it back on. If the picture gets better, repeat this manipulation several times.
If the first option didn't help, then don't worry. You can demagnetize your TV screen using throttle for demagnetizing the kinescope.

The principle of operation of the choke for demagnetizing a picture tube is a smoothly disappearing alternating magnetic field. When operating the throttle, do not make any sudden movements, as this may lead to re-magnetization of the TV screen.

How to make a choke to demagnetize a TV screen

A simple choke for demagnetizing a TV screen can be made from improvised means. To do this you will need a mandrel, PEL-2 wire, electrical tape, an on/off button and a 220V wire.

Let's take it a 100 mm mandrel, wrap it with PEL-2 wire (900 turns) with a diameter of 0.15 mm, insulate it all and connect the on/off button with a 220V wire. Device for demagnetizing a TV screen ready.

We turn on the TV in advance for 10-15 minutes, connect the choke at a distance of 2 meters. We begin to make large circular movements, slowly approaching the TV. When approaching the TV, reduce the rotation radius. Then, also slowly move back to the starting point. Allow for the entire procedure 40 seconds for yourself, do not let the throttle overheat.

Chokes for demagnetizing the TV screen can also be made from a coil of a magnetic starter or from a choke from old lamp daylight. In the first case, simply connect the coil to the network and, similar to a homemade choke, perform the operation to demagnetize the TV screen.
Do this with the choke from a fluorescent lamp - remove the metal casing from it, leave the winding and inner core. Solder to the winding power wire with a 220V plug and wrap the structure with electrical tape. We have obtained an electromagnet with a large dispersion field.

Good luck degaussing your TV screen.
Photo taken from the website telemasterskaya.rf

Master's answer:

There are times when color distortions appear on the screen of a CRT color TV due to magnetization of the mask. You can correct this situation by performing a procedure called degaussing.

To do this, you need to disconnect the TV from the network and wait until the posistor (the so-called thermistor that has a positive thermal coefficient of resistance) in the demagnetization loop circuit cools down. This may take about half an hour. After this, you need to turn on the device again. Automatic demagnetization should occur. If it does not help, you need to repeat this procedure several times.

As a rule, the monitor has a relay that disconnects the posistor and coil from the network after demagnetization has been carried out. Thanks to this, it cools down even when the monitor is on. In order to demagnetize the picture tube again, it will be enough to select an item in the monitor menu called Degauss. Do not forget that it will be possible to repeat successful demagnetization of the tube mask only after half an hour (while the posistor is still hot, by selecting the appropriate menu item, the relay will click, but demagnetization will not occur, moreover, each such attempt will reheat the posistor) .

The kinescope can be so magnetized that it is impossible to demagnetize it with the built-in loop. Then it is necessary to use an external demagnetizing choke. For these purposes, it can be borrowed from a television studio.

For the time being, remove from the room all disks and floppy disks, audio and video cassettes, magnetic stripe tickets, bank and discount cards, in general, everything that can be demagnetized in the process of company with a TV or monitor. Then you can turn on the TV or monitor, place the throttle a few meters away from it, and then turn it on too. Slowly move the throttle towards the device, moving it slightly from side to side; in the process, severe color distortion will appear on it. Just as slowly, take it back, and only a few meters away from it you can turn it off. After this procedure, color distortions should disappear. If this does not happen, repeat the process a few more times. You cannot keep the throttle on for a long time, this will cause it to heat up.

In a situation in which even demagnetization with an external choke did not lead to the result you wanted, the adjustment must be entrusted to a specialist, since most likely the convergence of the beams in the device is impaired. This is due not only to the presence of high voltages in the TV or monitor, but also to the complexity of the procedure: not even every TV technician will undertake it.

Hi all!

Quite often, in the practice of repairing CRT TVs, there is such a malfunction as the appearance of color spots on the screen or seemingly unreasonable blowing of a protective fuse.

Colored spots , mainly, are formed in the corners of the kinescope and do not appear simultaneously, but over a certain period of time. It may seem that the manifestation of such a malfunction tells us about failure kinescope , but I hasten to reassure you, kinescope not to blame here and is fully functional. This “spotty” image indicates demagnetization or magnetization screen our TV.

If the TV was not turned off from the network for a long time, but was turned off using the remote control (it was in standby mode), then magnetization of the kinescope may occur. The fact is that in most CRT TVs, the demagnetization system starts working when the TV is turned on to the network, and if the device is constantly connected to the network, then demagnetization does not occur when the TV is turned on from the remote control.

The principle of the demagnetization system is as follows: when you turn on the “network” button on the TV, voltage begins to flow to the posistor, which, in turn, powers the kinescope demagnetization loop located on its bandage, i.e. on the back of the screen. When the TV is demagnetized, the posistor limits the power supply to the loop. And so on every time you turn on the TV. And if your device is constantly in standby mode, i.e. turns on and off only from the remote control, then the power is on posistor and the power supply is supplied continuously (this can be observed by looking at the LED on the TV panel) and the demagnetization system is constantly disabled. That is why it is recommended to disconnect the TV from the 220 V network at least once a week.

« posistor is an ordinary thermistor that changes resistance depending on temperature. In a cold state, the resistance of the posistor is very small (5 - 15 Ohms), in a heated state it is more than 10 kOhms. The posistor is connected directly to the TV's power circuit in series with the demagnetization loop. When the TV is connected to the network, the resistance of the posistor is low and current flows through it to the demagnetization loop. After heating, the posistor gives greater resistance, which prevents the passage of voltage to the loop. By design posistors may differ, but they are all interchangeable.”

This malfunction can also appear if the posistor itself fails. If you turn your TV off and on from the network several times, and the spots do not disappear, then this indicates a failure of the posistor, which should be replaced.

Another option in which a posistor may be to blame is when the mains fuse burns out. The power supply is in good condition. In a posistor, in this case, when voltage is applied to it, short circuit and, accordingly, the entire voltage supply to the TV is short-circuited. As a result, the protective fuse blows.

Replacement posistor

Replacing a posistor is not particularly difficult, nor does it require any special knowledge.

You need to unscrew the back cover of the TV, pull out the board on which the radio components are located and find the plug for turning on the demagnetization loop. As a rule, a posistor is located directly next to this plug. The failed part must be desoldered and a new one or a known good one must be soldered in its place.

That's all, actually!

If you have any questions or have any suggestions or comments, you can put them in the comments.