How do I fix the TV screen, my niece was experimenting with a magnet?

Question

She put the magnet on the TV screen and the colors are all wrong now...lol. There's this weird spot right in the middle. What should I do?

Answer 1

""My four-year-old son was fooling around with a magnet, and when I was turned away, put it right on our TV screen. I then saw him doing this, and before I could bring myself to think consequences, we were both mollified by the amazing and colorful patterns it created on the screen. He sort of moved it around the screen, like you would an eraser on a black board. Well, when he removed the magnet, the screen had been drained of its normally saturated colors, and what we now have left is a color TV with only three colors, basically green, blue, and red. And they are not solid and deep like they were before. They are rather faded, and arranged in three distinct blotches, if you will. Are we stuck with this situation forever, or will this aberration fade with time, back to normal? And, why did this happen? -- E-S.B.""

Your son has magnetized the shadow mask that's located just inside the screen of your color television. It's a common problem and one that can easily be fixed by "degaussing" the mask (It'll take years or longer to fade on its own, so you're going to have to actively demagnetize the mask). You can have it done professionally or you can buy a degaussing coil yourself and give it a try (Try a local electronics store or contact MCM Electronics, [phone], 6" coil is item #72-785 for $19.95 and 12" coil is item #72-790 for $32.95).

Color sets create the impression of full color by mixing the three primary colors of light--blue, green, and red--right there on the inside surface of the picture tube. A set does the mixing by turning on and off three separate electron beams to control the relative brightnesses of the three primary colors at each location on the screen. The shadow mask is a metal grillwork that allows the three electrons beams to hit only specific phosphor dots on the inside of the tube's front surface. That way, electrons in the "blue" electron beam can only hit blue-glowing phosphors, while those in the "green" beam hit green-glowing phosphors and those in the "red" beam hit red-glowing phosphors. The three beams originate at slightly different locations in the back of the picture tube and reach the screen at slightly different angles. After passing through the holes in the shadow mask, these three beams can only hit the phosphors of their color.

Since the shadow mask's grillwork and the phosphor dots must stay perfectly aligned relative to one another, the shadow mask must be made of a metal that has the same thermal expansion characteristics as glass. The only reasonable choice for the shadow mask is Invar metal, an alloy that unfortunately is easily magnetized. Your son has magnetized the mask inside your set and because moving charged particles are deflected by magnetic fields, the electron beams in your television are being steered by the magnetized shadow mask so that they hit the wrong phosphors. That's why the colors are all washed out and rearranged.

To demagnetize the shadow mask, you should expose it to a rapidly fluctuating magnetic field that gradually decreases in strength until it vanishes altogether. The degaussing coils I mentioned above plug directly into the AC power line and act as large, alternating-field electromagnets. As you wave one of these coils around in front of the screen, you flip the magnetization of the Invar shadow mask back and forth rapidly. By slowly moving this coil farther and farther away from the screen, you gradually scramble the magnetizations of the mask's microscopic magnetic domains. The mask still has magnetic structures at the microscopic level (this is unavoidable and a basic characteristic of all ferromagnetic metals such as steel and Invar). But those domains will all point randomly and ultimately cancel each other out once you have demagnetized the mask. By the time you have the coil a couple of feet away from the television, the mask will have no significant magnetization left at the macroscopic scale and the colors of the set will be back to normal.

Incidentally, I did exactly this trick to my family's brand new color television set in 1965. I had enjoyed watching baseball games and deflecting the pitches wildly on our old black-and-white set. With only one electron beam, a black-and-white set needs no shadow mask and has nothing inside the screen to magnetize. My giant super alnico magnet left no lingering effect on it. But when the new set arrived, I promptly magnetized its shadow mask and when my parent watched the "African Queen" that night, the colors were not what you'd call "natural." The service person came out to degauss the picture tube the next day and I remember denying any knowledge of what might have caused such an intense magnetization. He and I agreed that someone must have started a vacuum cleaner very close to the set and thus magnetized its surface. I was only 8, so what did I know anyway.

Finally, as many readers have pointed out, many modern televisions and computer monitors have built-in degaussing coils. Each time you turn on one of these units, the degaussing circuitry exposes the shadow mask to a fluctuating magnetic field in order to demagnetize it. If your television set or monitor has such a system, then turning it on and off a couple of times should clear up most or all of the magnetization problems. However, you may have to wait about 15 minutes between power on/off cycles because the built-in degaussing units have thermal protection that makes sure they cool down properly between uses.

Answer 2

WAIT! I did the exact same thing. BUT i used the magnet to drag the colour back to normal! It took me a while of moving the magnet around the screen but FINALLY i got the colours back to normal and you can not tell that the colour was sucked out.

Answer 3

If your TV has a built in degaussing coil, it will make a loud buzz or hum for for three or four seconds when it is first turned on. You can degauss this way, but it may take a few cycles. This is why many techs will tell you "it will fade with time".  Note that the set needs to be turned off for about twenty minutes between cycles for the degauss circuit to reset.  

If you have a degaussing coil ( http://www.starkelectronic.com/gc9317.ht... ), you can do the following.  The coils are pretty inexpensive.

1. Turn on the TV

2. Make sure the power switch on the coil if off and plug it in.

3.Stand at least 6 feet away from the screen and point the EDGE of the coil at the screen.

4. Turn on the coil. DO NOT TURN OFF THE COIL UNTIL THE END OF THE PROCEDURE. Point the center hole at the screen. Start moving the coil in large circles parallel to the face of the screen.

5. Slowly move toward the screen making the circles smaller. Visualize a spiral coming from the front of the screen.

6. When at the screen move the coil all over the screen area. The picture will distort - it's supposed to do that! Cover the front of the screen well.  Take your time . . .

7. Reverse the approach procedure. Move away from the screen making increasingly larger circles until you are standing at your starting point.

8. Turn the EDGE of the coil toward the screen.

9. Turn the coil off.

Note, turning the coil on or off near the screen can magnetize the screen and actually make the situation a bit worse.

The above procedure is what a TV repair man would do in his shop.  You could take the set to a shop to have it degaussed.

I hope this helps.  Please return and select a Best Answer from all of those submitted.

Answer 4

Don't do anything......

The TV set has a built-in DEMAGNETIZER.....

When you first turn it on, is when it demagnetizes.....

Let it do it's job.

Answer 5

Look, if the TV has a so called "Degaussing" Button or Menu entry.

The magnet has magnetized the hole mask of the TV and now the magnetism guides the electron beam into the "wrong" holes of the mask resulting in a discolored screen.

If your TV doesn't have a degaussing option, you have to bring it to a service techician who can degauss it for you.

This "repair" should be relatively cheap, as no parts have to be exchanged.

He will wave a degaussing coil over the screen and demagnetize the mask.

Then your TV should be back to normal.

Answer 6

tou can try going to the menu butoon on remote or tv and go to color or brightness and ajust it to the best picture but the spot will most likely never go away and it might be broken stong magnets will mess up tvs