Can I degauss my TV with a magnet?

[Nick Alexander]

I have got some green patches on my TV since I moved my speakers too close
to the tube. Can I use a magnet to get rid of the colours?

Regards,
Nick Alexander

 

[Ron]

If you mean a permanent magnet, no, that's what caused the problem in the
first place. Most TV's have a built-in degaussing circuit that works
automatically when the set is switched on. Otherwise, you need to use a
degaussing coil, powered by AC. I have also used an AC powered demagnetizer
(for erasing recording tape) made by R. B. Annis. You start by applying
power to the coil. Move it close to the screen and around in a circular
motion to cover the entire area, then gradually move it a couple of feet
away and turn the power off.
-Ron
(email: replace 'abuse' with 'cyberguy3k')

 

[Jerry G.]

NO. A permanent magnet will end up making the fault worse, and if strong
enough, it can do permanent damage. An AC or alternating field is required.
There are hand held degassing coils that are made for manually degassing
tubes. When a new CRT is installed, it is common practice to manually
degaussed it before doing the initial purity and convergence alignment.

The internal degaussing coil should do the job of demagnetizing the CRT mask
if it is working properly, the purity alignment is okay, and the mask is not
damaged.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


I have got some green patches on my TV since I moved my speakers too close
to the tube. Can I use a magnet to get rid of the colours?

Regards,
Nick Alexander

 

[Sam Goldwasser]

I have got some green patches on my TV since I moved my speakers too close
to the tube. Can I use a magnet to get rid of the colours?

In principle this is possible and I have used it in a pinch but the
proper AC degaussing coil approach is much easier.

See the CRT FAQ: http://www.repairfaq.org/sam/crtfaq.htm .

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
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[Ken Weitzel]

In principle this is possible and I have used it in a pinch but the
proper AC degaussing coil approach is much easier.

In the olden days (as my grand daughter refers to them
a Weller gun worked quite well if you you were without
a coil...

Ken

 

[John Todd]

I have got some green patches on my TV since I moved my speakers too close
to the tube. Can I use a magnet to get rid of the colours?

Regards,
Nick Alexander

If I may presume to clarify Jerry and Sam's wisdom, you use
the internal degausser when you turn the power on, so turn your
set off and on a couple of times!

 

[ajb]

In principle this is possible and I have used it in a pinch but the
proper AC degaussing coil approach is much easier.

Yes, dangerous but possible. You use the old watchmaker's technique - a
strong horse-shoe magnet mounted on the end of a hand-drill to spin it
fast.

As Sam says, "in a pinch".... and indeed I have used this method. But I
wouldn't advise it any more.
--
ajb

"If the spirit of the ruler rise up against thee, leave not
thy place; for yielding pacifieth great offences."
(Ecclesiastes 10-4)

 

[Sam Goldwasser]

Yes, dangerous but possible. You use the old watchmaker's technique - a
strong horse-shoe magnet mounted on the end of a hand-drill to spin it
fast.

As Sam says, "in a pinch".... and indeed I have used this method. But I
wouldn't advise it any more.

And, as most of us neglected to mention the first time, just power cycling
the TV a few times (30 minutes off, 1 minute on) will likely clear it up
by activating the built-in degausser. Or, just wait a few days and this
will happen automagically.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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Important: The email address in this message header may no longer work. To
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[[email protected]]

I have got some green patches on my TV since I moved my speakers too close
to the tube. Can I use a magnet to get rid of the colours?

Regards,
Nick Alexander

Are the speakers still too close? If they are, then the problem isn't
going to go away. You need shielded speakers if you want them that
close.

If this is a leftover from exposure to the speakers, then the normal
degaussing mechanism built-in to the TV may take care of this. Might
take several power cycles - wait several minutes between each cycle
for the coil/ptc to cool down otherwise you won't be getting much in
the way of field strength. Or just wait a few days of normal usage

-Chris

 

[eddumweer]

Or get an old degaussingcoil, mount it safely into a bigger wooden box,
place a pushbutton (contact when pussed) then connect it to the mains.

Usage is to switch of the tv, put everything away like waches and other
magneticly to disturbing parts.

Put it to the face of the picturetube, push the button and walk away
straight ahead from the tv and release the switch at 1,5 meter or 5 foot.

Greetings Peter

 

[George R. Gonzalez]

So much disinformation!

You can demagnetize the TV with a magnet, no problem, just takes 30 seconds
of careful waving it around. Start out close to the TV twirling the magnet
around so that both North and South ends of the magnet alternately point
toward the TV. Keep twirling while you slowly move the magnet farther
away. Keep doing this until you can't see any effects on the screen.

Don't worry very much about any *stationary* magnets, like speaker magnets
near your TV. The most they can do is make the whole picture deflect a bit.
If you don't notice any slant or twist to the picture, you can live with the
magnets. To get color effects, the magnets would have to be MOVING in order
to magnetize the CRT mask. Not moving ==>no magnetizing of the mask ==> no
color funnies.

 

[[email protected]]

So much disinformation!

You can demagnetize the TV with a magnet, no problem, just takes 30 seconds
of careful waving it around. Start out close to the TV twirling the magnet
around so that both North and South ends of the magnet alternately point
toward the TV. Keep twirling while you slowly move the magnet farther
away. Keep doing this until you can't see any effects on the screen.

Don't worry very much about any *stationary* magnets, like speaker magnets
near your TV. The most they can do is make the whole picture deflect a bit.
If you don't notice any slant or twist to the picture, you can live with the
magnets. To get color effects, the magnets would have to be MOVING in order
to magnetize the CRT mask. Not moving ==>no magnetizing of the mask ==> no
color funnies.

Of course a real strong magnet can deform or damage the shadow mask.
I had a co-worker who didn't believe me and stuck a magnet from a HD
on his monitor - permanent fuzzy spot. BTW, this magnet has no
problem holding a magazine to my office wall that has metal studs
under the drywall.

-Chris.

 

[Mark D. Zacharias]

I seriously doubt this will fix anything. If it ever worked for you,
consider yourself lucky.


Mark Z.

 

[JD]

Place a small speaker or 2 on top of the tv or near it, with the tv on, turn
or angle it until the color goes back to normal. but you have to leave the
speaker their for a week or more.

 

[Doug Goncz]

Sure you can. You must spin the magnet with a motor to generate an alternating
magnetic field, then bring this field towards and away from the tube very
slowly to "erase" the permanent magnetization that caused the green spot.

An Alnico horseshoe magnet with mounting hole at the bride, a bolt, and an
electric drill might do, but this reply is intended to generate some
controversy so I will include the fact that rotating a permanent magnet on any
conceivable axis with any conceivable equipment generates an alternating field
of much lower quality than that produced by house current through the usual
degaussing coil.

Don't mean to stir up the water, but you can tinker with this to learn
something, then degauss properly.

You see, the alternating field must completely and symmetrically reverse to
average out to null. A rotating permanent magnet can have a bias on some axis.


Yours,

Doug Goncz ( ftp://users.aol.com/DGoncz/ )

My physics project at NVCC:
http://groups.google.com/groups?q=dgoncz&scoring=d plus
"bicycle", "fluorescent", "inverter", "flywheel", "ultracapacitor", etc.
in the search box

 

[na]

What the hell are people giving out the wrong way to degause a crt.

Here's how u do it: with tv on, unplug it from ac mains (power from
the wall), wait 5 sec, plug it back in & turn it on. the built in
degausing coil will degaus tube. every color tv or monitor has a
built in degausing coil.

or u can use an after market degausing coil to degaus (one that is
properly made for the job), otherwise damage can be done to the shadow
mask (inside tube just behind front surface glass), little lone flying
debree from a drill....

 

[Sam Goldwasser]

What the hell are people giving out the wrong way to degause a crt.

Here's how u do it: with tv on, unplug it from ac mains (power from
the wall), wait 5 sec, plug it back in & turn it on. the built in
degausing coil will degaus tube. every color tv or monitor has a
built in degausing coil.

Yes, but your method may not work as some/many/most require time for
a thermistor to cool down. 20 seconds on, 20 minutes off, few cycles
like that may be needed.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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Important: The email address in this message header may no longer work. To
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