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Science Forum Index » Electronics - Misc Forum » Degauss TV screen
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| JRRR |
 Posted: Fri Dec 29, 2006 7:25 pm |
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A magnet was swiped across my TV screen, leaving a purplish swath. Is
there a way to fix this problem? |
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| DaveM |
| Posted: Fri Dec 29, 2006 9:16 pm |
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"JRRR" <jrrroach@sonic.net> wrote in message
news:1167434719.534143.218410@a3g2000cwd.googlegroups.com...
Quote: A magnet was swiped across my TV screen, leaving a purplish swath. Is
there a way to fix this problem?
Yes, there is a tool called a "Degaussing Coil" (imagine that!!!). You can buy
one from online vendors
http://www.mcminone.com/product.asp?catalog%5Fname=MCMProducts&product%5Fid=72%2D785
http://www.elexp.com/cpt_1dgc.htm
Other vendors might also stock them... Google for "degaussing coil"
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)
Some days you're the dog, some days the hydrant. |
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| Homer J Simpson |
| Posted: Fri Dec 29, 2006 11:07 pm |
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"JRRR" <jrrroach@sonic.net> wrote in message
news:1167434719.534143.218410@a3g2000cwd.googlegroups.com...
Quote: A magnet was swiped across my TV screen, leaving a purplish swath. Is
there a way to fix this problem?
Leave it be. It will fix itself. Unless you know what you are doing you may
make it worse.
If you do know what you are doing try a video tape degausser with the usual
precautions. |
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| Impmon |
| Posted: Fri Dec 29, 2006 11:07 pm |
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On Fri, 29 Dec 2006 20:16:21 -0500, "DaveM"
<masondg4499@comcast99.net> wrote:
I have a set of coils salvaged from a monitor. It was wired for
direct 110v operation via a thermal resistor to shut it off after
initial power up and degaussing. Can I just wire a standard 110v plug
with a N.O. push button switch instead to zap anything that needs
clearing up? |
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| JRRR |
| Posted: Sat Dec 30, 2006 3:10 am |
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Homer J Simpson wrote:
Quote: "JRRR" <jrrroach@sonic.net> wrote in message
news:1167434719.534143.218410@a3g2000cwd.googlegroups.com...
A magnet was swiped across my TV screen, leaving a purplish swath. Is
there a way to fix this problem?
Leave it be. It will fix itself. Unless you know what you are doing you may
make it worse.
If you do know what you are doing try a video tape degausser with the usual
precautions.
Dho! It fixed itself. Thanks everybody! Let's all get degaussed! |
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| jasen |
| Posted: Sat Dec 30, 2006 4:54 am |
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On 2006-12-29, JRRR <jrrroach@sonic.net> wrote:
Quote: A magnet was swiped across my TV screen, leaving a purplish swath. Is
there a way to fix this problem?
you can try to erase it using the same magnet reversed, this won't be
perfect,
or give it a few weeks, it'll fade gradually.
Or if you're in a hurry you can erase the mark using an ac powered
electromagnet.
Or take it to a TV repairman, it's a 2 minute job.
Bye.
Jasen |
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| jasen |
| Posted: Sat Dec 30, 2006 4:56 am |
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On 2006-12-30, Impmon <impmon@digi.mon> wrote:
Quote: I have a set of coils salvaged from a monitor. It was wired for
direct 110v operation via a thermal resistor to shut it off after
initial power up and degaussing. Can I just wire a standard 110v plug
with a N.O. push button switch instead to zap anything that needs
clearing up?
If you have 110V (ish) AC, then yes.
if it gets hot let it cool down.
Bye.
Jasen |
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| Art |
| Posted: Sat Dec 30, 2006 10:33 am |
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Depending on what type of set you have, a lot of new SONY televisions can
be permantly damaged by using a degaussing coil on the crt. The aperture
grill assembly can be dislodged or damaged within the crt rendering it
useless and requiring a new crt to be installed. Since you did not post make
and model number of the set this is sent for informational purposes only.
"jasen" <jasen@free.net.nz> wrote in message
news:en59gu$i8s$2@jasen.is-a-geek.org...
Quote: On 2006-12-29, JRRR <jrrroach@sonic.net> wrote:
A magnet was swiped across my TV screen, leaving a purplish swath. Is
there a way to fix this problem?
you can try to erase it using the same magnet reversed, this won't be
perfect,
or give it a few weeks, it'll fade gradually.
Or if you're in a hurry you can erase the mark using an ac powered
electromagnet.
Or take it to a TV repairman, it's a 2 minute job.
Bye.
Jasen |
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| sundar |
| Posted: Sat Dec 30, 2006 12:48 pm |
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JRRR wrote:
Quote:
Dho! It fixed itself. Thanks everybody! Let's all get degaussed!
Can anyone here explain how it did this? That is, how did a TV affected
by a magnetic field clear itself without any outside help? |
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| CWatters |
| Posted: Sat Dec 30, 2006 3:12 pm |
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"sundar" <sundaryourfriend@gmail.com> wrote in message
news:1167497311.612626.247660@48g2000cwx.googlegroups.com...
Quote:
JRRR wrote:
Dho! It fixed itself. Thanks everybody! Let's all get degaussed!
Can anyone here explain how it did this? That is, how did a TV affected
by a magnetic field clear itself without any outside help?
Perhaps it has a built in degauss coil like many CRT monitors. They are
activated at switch on so power cycling it a few times may have fixed it. |
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| Homer J Simpson |
| Posted: Sat Dec 30, 2006 3:15 pm |
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"sundar" <sundaryourfriend@gmail.com> wrote in message
news:1167497311.612626.247660@48g2000cwx.googlegroups.com...
Quote:
JRRR wrote:
Dho! It fixed itself. Thanks everybody! Let's all get degaussed!
Can anyone here explain how it did this? That is, how did a TV affected
by a magnetic field clear itself without any outside help?
All color TVs have a circuit to do this which runs once when you switch on.
If the magnetization is severe it may take a few times. |
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| scada |
| Posted: Sat Dec 30, 2006 4:49 pm |
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"JRRR" <jrrroach@sonic.net> wrote in message
news:1167434719.534143.218410@a3g2000cwd.googlegroups.com...
Quote: A magnet was swiped across my TV screen, leaving a purplish swath. Is
there a way to fix this problem?
All crt tv's have a built in degaussing circuit. They use a PTC (positive
temperature coefficient) resistor to limit the current through the
degaussing coil. Therefore when the TV is first turned on, the coil sees a
large current, as the PTC heats up the current decreases (resistance
increases) until it reaches a very low current that won't affect the CRT
deflection. When the set is turned off, the PTC cools down, lowering it's
internal resistance for the next TV turn on. If you just cycle the set
normally eventually it should correct itself. |
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| jasen |
| Posted: Sat Dec 30, 2006 6:31 pm |
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On 2006-12-30, sundar <sundaryourfriend@gmail.com> wrote:
Quote:
JRRR wrote:
Dho! It fixed itself. Thanks everybody! Let's all get degaussed!
Can anyone here explain how it did this? That is, how did a TV affected
by a magnetic field clear itself without any outside help?
They use a type of steel that doesn't retain magnetism well,
there is also a degaussing coil attached behind the screen
(it's what makes the "fong" sound when you turn the set on)
--
Bye.
Jasen |
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| John Fields |
| Posted: Sat Dec 30, 2006 6:55 pm |
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On 30 Dec 2006 08:48:31 -0800, "sundar" <sundaryourfriend@gmail.com>
wrote:
Quote:
JRRR wrote:
Dho! It fixed itself. Thanks everybody! Let's all get degaussed!
Can anyone here explain how it did this? That is, how did a TV affected
by a magnetic field clear itself without any outside help?
---
It has its own degaussing coil that comes on every time you turn on
the TV.
--
JF |
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| JANA |
| Posted: Sun Dec 31, 2006 11:37 am |
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Your TV's internal degaussing coil should eventually take care of the
problem. After a number of power cycles over a period of time should clear
it up. If you turn the set off for about an hour, and turn it on, the
degaussing coil should activate. I would not suggest cycling the set's power
on and off specifically to degauss the screen. Start-ups are hardest on any
electronic devices.
The quicker and more sure way to degauss the screen is to get a degassing
coil that is designed for that purpose. Any of the TV service people who
have been replacing CRT's and servicing TV sets, should have one. See if you
can put down a deposited to borrow or rent it, or simply have their tech
come over and degauss your set. The service call would probably be cheaper
than buying one that you may only use one time in the life of the set. Your
next set will most likely be a Plasma or LCD type screen. There are no
degaussing problems with these.
Sometimes, when a magnet is swiped across a CRT, the mask can be damaged. If
this is the case, then the damage is permanent, and the only fix is to
replace the CRT. A CRT replacement is not worth the money for any consumer
set.
--
JANA
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"JRRR" <jrrroach@sonic.net> wrote in message
news:1167434719.534143.218410@a3g2000cwd.googlegroups.com...
A magnet was swiped across my TV screen, leaving a purplish swath. Is
there a way to fix this problem? |
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