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Magnets and TV's

03-10-2006, 06:17 AM
i know most of us did this when we where little kids, pass a magnet over your parents TV LOL!..yup..

anyway the corner of my TV has a rather purple spot...does anyone know of a method to fix this? i thought by using a magnet one could somehow remove it/fix it...thx

03-10-2006, 10:33 AM
You need to get a degauser coil. You might also try a high wattage soldering gun turned sideways if you have one. Basically you wave the coil (or side of the soldering gun while on) over the face of the tube and the alternating magnetic fields will degause the tube.

03-10-2006, 02:25 PM
where can i find a degauser coil?!?!?! home depot? sears LOL... i was reading online and some tv's havea degauser feature built in..others do it automatically..to bad this isnt the case for me..

i also read that you can take a smaller magnet and try to "draw out" the color from center outwards..i tried it abit and it worked just abit.. i also read that you can turn the TV on and off rapidly..not sure what that does but i tried it, nothing happened, only thing i could think of is that it'll mess up the tv more LOL!..

how much do those coils cost??

03-10-2006, 03:41 PM
I once messed up my 20" JVC analog tube TV real bad with the speaker magnets in my Infinity Kappa unshielded speakers. Usually when you move the speakers away, the discolorizations immediately go away too. When the discolorizations stay even when the speakers are gone, you've really messed up your screen, and that's what I had done.

But, I was able to fix my TV back to 100% perfect operating condition by simply re-using those same speakers and waving them around my TV trying to draw out the color. So I guess it may be possible, but admittedly it is probably dangerous. A real degaussing coil is much better if you have one, or the soldering gun advice is probably great too.

Did you discolor your TV yourself with a magnet by accident? If you didn't, if it just became like that one day or has always been like that, sometimes it is because something is actually wrong with the set and it can't be degaussed. I have a 20" Dell Trinitron monitor that is currently like that. Someone (else) dropped it and caused the problem. I think one of the magnets inside the monitor probably got shifted, so the only fix is to open up the monitor and repair it (which I haven't done, I'm just ignoring the problem as it's not that severe).

Turning the TV on and off will only work if your TV automatically degausses every time it is turned on. A lot of TVs don't degauss when turned on unless they've been off for some time. You'll know if a TV degausses when powered on because it will make a BYOING noise. Rather than turn the TV on and off rapidly, just ignore the problem and see if it goes away over a period of weeks. That way the TV will be trying to degauss itself naturally. If that method fails then you either need the degaussing coil, or you may actually need your TV fixed (if the problem lies with the tube gun itself and not the shadow mask screen being magnetically charged).

03-10-2006, 03:57 PM
Radio Shack used to sell them, but I don't think they do anymore. Here is one you can get over the net:

03-11-2006, 12:36 AM
Radio Shack used to sell them, but I don't think they do anymore. I used to have a 1 foot diameter roll (about 300ft) of 22 or 18ga "bell wire" = 100 turns or so -it could be hooked up to 110v for about a minute without overheating and did a pretty good job of degaussing older color TVs - of course it won't meet any safety standards - 500 feet (200 turns) would be better - remember to move the degaussing coil several feet from the TV before turning it off otherwise that last cycle will remagnetize the TV again :mad: here's a DIY online version http://www.oscarcontrols.com/degauss/index.shtml

03-11-2006, 01:14 AM
here's some instructions
http://www.mainelectronics.com/degaussing.htm Operating Instructions
This product must not be operated for more than one minute continuously. After using for one minute do not operate for thirty minutes to allow unit time to cool.
To use, plug unit into receptacle near TV or Monitor to be degaussed. Move as far as possible from set (minimum of 6 ft.) and press switch. Holding the coil so that the plane of the coils is parallel to the front of the tube, move coil in a circular motion while approaching the face of the screen. Continue the circular motions passing over the complete surface of the screen until you are within inches of the screen. While continuing this motion move slowly away form the screen until you are as far away as possible, then release switch.also http://twobits.com/Degauss/

03-11-2006, 01:56 AM
I have a similiar spot on the upper right hand corner of my set although it yellowish and pretty faint except when there is a very light color(sky blue for example). I used to have my center main on the tv as I did on my previous set but maybe this caused my problem as well.How bout this soldering iron trick?Soldering iron I have,degaussing coil I dont nor would I prefer to purchase one if I can try this iron move.Can someone tell me how to try this?Thanks

03-11-2006, 11:25 AM
A soldering iron will not put out enough of a field to work. A soldering gun has a lot more coils and is bigger. Even then a gun can be iffy, depending on how severe the magnitism of the tube is. The coil is a better solution.

03-11-2006, 08:00 PM
k so my question again, where the heck can i find a gun or coil like that... im assuming you cant buy them????.

a few weeks wont do the trick, this "spot" on my TV has been their HONESTLY for many many many many years..its a 10yr old Tv (manufacturer in 1996) and i got it in 96 also..i think it was in like 1999 or 2000 that the "spot" appears when i had my TV and surround sound system set up...the speakers must have intered "gradually over time" because it never became visible from one day to the next..it was just over time and now its very noticiable...and its been the exact same for about 2-3yrs. i use the magnet method to draw it out alittle..works only alittle though..it clears it up pretty much all of it when i have the magnet right up close to it(its a very small refridgerator magnet) but overall i think its pretty much permanent. if i can buy a gun or something then i would but i dont know where to look..

03-11-2006, 08:42 PM
Radio Shack used to sell a cheap bulk tape eraser which put out a huge magnetic field--you may still find one in stores.

You could check out www.degaussers.com (yes, I'm serious), but I don't know if you're going to find it worth it.



They rent equipment, too.

If you decide to roll your own, be *very* careful. You're basically putting a wire across your household power. Avoid: electrocuting yourself, starting a fire or burning yourself with the hot coil, blowing your breaker, etc.

Other things you might try: cheap hairdryers (the better ones are designed to minimize EMF), electric blankets, electro-mechanical doorbells.

03-11-2006, 08:47 PM
k. My answer again: http://www.alliedelec.com/Search/ProductListing.asp?ID=752&Desc=Degaussing+Coil&IND=T&SEARCH

03-11-2006, 09:35 PM
www.degaussers.com is cheaper for the same unit :)

03-12-2006, 04:02 PM
If you decide to roll your own, be *very* careful. You're basically putting a wire across your household power. Avoid: electrocuting yourself, starting a fire or burning yourself with the hot coil, blowing your breaker, etc..We're adults here - :rolleyes:

03-13-2006, 02:38 PM
All adults aren't familiar with voltage, current and resistance--better safe than sorry :)

03-13-2006, 04:52 PM
Ok I see these degaussers but,if I cant even figure out which one I need to use to what I want to do with it,I should probably not even attempt this.How would you use one of them on a tv?Is there someone I can hire to come out and attempt to deguass(?) my screen?If so will this more than likely remove remove this patch of color or is it not even worth it since the spot is pretty small and being that its yellowish its barely noticeable,except to me since I look at it everyday.

03-13-2006, 05:30 PM
Look at maicaw's link to instructions earlier in the thread.

Basically anything that generates a strong electromagnetic field will work, but degaussers that are designed for TV will be easiest to use and most likely to work. You turn it on away from the set, move it close to the tube and pass it over the bad area, then move it away before turning it off.

The cheapest one should work fine. Only you can decide if it's worth it. What you are describing might not actually be a problem with the screen being magnetized, in which case degaussing won't help (although if you had speaker near the bad spot, it's pretty likely).

03-13-2006, 07:44 PM
www.degaussers.com (http://www.degaussers.com/) is cheaper for the same unit :)
The one in your link is $99.
The one in my link is $55.
Not much difference.

03-13-2006, 07:51 PM
$60 to $99 for a coil... call a service repair center to help you.

Circular motions...like the number 8....dancing the coil across and around the screen... kinda like voodoo magic...drawing the magnetic sickness out of the tube. Thats the best I can describe it.

There is a fine delicate art to degaussing a tv tube and the process should be left in the hands of a pro (no pun intended) and NOT a novice.

Granted the tinkerer in us would like to try it ourselves ...but the process can become UGLY if you do not know what you are doing.

03-13-2006, 10:08 PM
$99.00 is the "regular price", scroll down to the "sale price", which is $49.99.

Personally, I wouldn't even pay that much for such a small problem, but that's me.

You have to be pretty sloppy to mess things up with a real degausser. I haven't had occasion to do it in years, but I never found it particularly difficult.

03-13-2006, 10:31 PM
Good for you Bobby!!!

03-14-2006, 12:37 AM
Yea its minor but you all can understand how something ene monor can drive you nuts.I'm gonna call around 2moro to see if any local repairmen do this and what it costs.I'll let you guys know how I make out.

03-14-2006, 05:10 PM
I figure it can't be that hard to degauss a CRT shadow mask (assuming that is in fact the problem; not always the case with magnetic discolorizations as I said earlier) with a real degausser. Especially considering I was able to degauss my old analog tube with my plain ol' unshielded bookshelf speakers. I just went and waved my 40 pound bookshelf speakers around the TV and eventually I got it to work. Again, I'm not recommending what I did, but I figure it can't be that hard with a real degausser.

03-14-2006, 07:49 PM
Today i called Best Buy and they took my phone 3 and said they would have a tech come to look at it,today nonetheless. So when the guy gets here he does some looking and toying with it to no avail. He also agreed that it may need to be degaussed(sp?) and that he was gonna call an independant tech to see if he could look at it.Obviously my next question was how much is this gonna cost me and he called back to the BB office and spoke to someone,who I'm not sure. He told me that BB authorized the use of this independant tech,whom he said is often used when problems are outside of the in-house techs knowledge or equipment is insufficient. So Saturday,this independant tech is coming,free of charge although I do have the $150 service plan,and is going to degauss my set or if thats not the solution I'm told he will do everything possible to eliminate this discoloration on my set. If all else fails I will return the set and exchange it for something else or they will credit me for the price of the set and I may upgrade to something better,although I love the CRT for the size of my room but perhaps a nice LCD would be cool with me.

03-17-2006, 11:21 PM
on occasion. It is about half the size of a tech guy's unit but it
bailed me out of a problem. Don't know if they still sell them. If you are at all technical, then make one using the guidelines posted earlier. The techs all made their own, a certain amount of 18 ga bell wire in loops with a 12" diameter, then one end each to the ends of a 110v cord and plug. Secure those connections (solder them is best) with wirenuts and tape the union, then a roll of black electrical tape around and around the 12" loop with the 110v wire coming out the bottom, and a cord switch near the coil. Then, follow the instructions to degauss. This will solve those annoying color problems. I wonder how many folks have dumped their TVs because some kid played with magnets near the TV or someone put an unshielded speaker near the tube. It happens.

03-18-2006, 09:42 AM
anyway i have some major good news(to be that is).. the purple spot in the upper left corner IS COMPLETELY GONE!!!!!!!!!!!!!!!!!! the TV looks brand new "I'm lovin it!"

all i did was draw it out with a small refregerator magnet like a week or so ago..then about 2 days ago me and my wife changed our living room around, the TV was moved, but not a little move, it was moved all the way across the whole room pretty much..its in front of the main window now and i cant believe the spot is all gone now..not a single trace...that is so freaking damn werid LOL!.. oh well im glade its all gone!..

03-18-2006, 12:11 PM
There must have been a magnetic field at the other place you had the TV. I should have recommended you try a compass to verify no magnetic fields exist.

03-18-2006, 09:21 PM
wow! I'm actually happry for ya.Gives me hope aswell. :thumbsup:

03-19-2006, 10:12 AM
the real fix for this problem was in unplugging and re-powering the TV.
Also there is a degauss button on the rear of many sets which will initiate the procedure. I think the problem corrected itself not from moving it but in repowering it. The degauss cycle initiates when the set is plugged in and turned on. The other likely explanation is that there was a magnet (from a clock, speaker, something with magnets in it) nearby where it was but not where it is now.

03-19-2006, 01:18 PM
If the internal deguaussing is working - you will hear an angry rattle or buzz at the time he turns the TV on - even with the remote - if it has been off even from the remote for 10 minutes or more -my newer XBR set takes even longer - maybe 30 minutes-- the thermistor or circuitry that slowly (over a 1 second period) shuts down the degausser during each use takes that long to cool off ,reset, or recycle in NASA-speak.
0r - deguassing circuit may be intermittent and a loose connection may have reconnected during the move.

03-20-2006, 09:46 AM
no i dont think my Tv has that auto degaussing feature since it was manufacturered in 1996 LOL. and no it doesnt make any buzzing sound when it turns on so i know it doesnt have it, i know what kind of sound it is cause my computer monitor has the deguas button in the OSD and i've used it before.

it is possible that the re-powering of the TV might have done the trick! since i did disconnect everything in order to move it...

but no i dont have a compass so i wouldnt be able to use a compass in that area to see if there was a magnetic field or not..but there must have been something there... oh well

03-20-2006, 01:42 PM
no i dont think my Tv has that auto degaussing feature since it was manufacturered in 1996 LOL. .Just to belabor the point ;) -I believe all brand name tvs have had that feature for the last 25-30 years at least - I have several sonys from the 1970s and they all have it to my recollection- and certainly my "daily-driver" analog 25XBR from 1985 has it - but yours may be an exception or broken. The only color TVs I recall that didn't automatically deguass themselves were the old round metal shelled color CRTubes used in the very early color sets - like RCAs. When the square all-glass CRTs came out -Sony's trinitrons etal <1970s - the need for manual degaussing seem to mostly disappear - I was moonlighting working on TVs back then - but soon as color video cameras became affordable I lost interest in the TVs - so maybe some old real TV tech has a more accurate memory archive. .

03-20-2006, 02:29 PM

this works

03-20-2006, 07:19 PM
Use big magnets. Pretty cool! They sell a magnetic prop-up tool in hardware stores, this would have potential I should think. Make sure the things are stuck really good to the drill shaft or heavy magnets will fly, put someone's eye out or break the CRT or even a window!

The early round tube (these CRTs were glass by the way, and all made by RCA even the ones in the Silvertones and Zeniths) and first rectangle tube sets did not have degaussers, but about the 4th or 5th generation - maybe a decade later, they began to appear in rectangular sets. When Sony started producing the Trinitrons, I don't recall if those had them or not, because they don't use conventional gun and shadow mask architectures. Our glass tube PC monitors mostly have metal shadow masks and therefore need internal degaussers. They work pretty well for normal disturbances. The tubes are so susceptible to this that if you were to perform a perfect electron gun convergence corner to corner - or pay a tech to do it - and then move the set 90 degrees L or R, you'd see the gun alignment change. Some positions would not align perfectly due to the effect of the N & S poles. In the early days of color TV, we never moved our sets because it could require a service call to get the convergence and degaussing right. That's assuming the tech didn't come in and ruin the thing in the process.

For a serious disturbance, a gentle repeat of the procedure a couple or three times should make progressive improvements.

03-20-2006, 08:00 PM
The early round tube (these CRTs were glass by the way, and all made by RCA even the ones in the Silvertones and Zeniths) .
I had a new GE branded color set that was I believe actually a RCA chassis and picture tube in the early 60s- it had a metal section between the neck and the screen as in this description of the developmental version - mine was probably the 21AXP22 metal cone picture tube commercial version - looked similar to this 1954 RCA model http://www.earlytelevision.org/rca_21ct55.html--The 21-CT-55 was RCA's second production set. It was introduced in November of 1954 and was made for about six months. It uses a chassis that is very similar to the CT-100, and a 21AXP22 metal cone picture tube. The picture tube appears to be original and is good. These sets are more rare than the CT-100.60s RCA C73293C Developmental Color Tube
(http://www.earlytelevision.org/rca_developmental.html) It is a variation of the 16" metal shell tubes in the RCA line. The mask and phosphor assembly was in a separate front piece and aligned in a sort of light tunnel, then welded to the rear bell. The weld ridge became the anode connection. RCA went wrong from the beginning.
This tube was use in the tri-color models 1 and 2 and possibly the 2A. Model 1 was the first RCA demo to the FCC. These tubes were circa April, 1950 to February, 1952. Models 3 and 3A used a 3-bolt version. Starting with the 3, they improved the trajectory of the guide bolts for the shadow mask alignment. The model 4 appears to be the first of the glass tubes. ....

03-20-2006, 11:21 PM
i was actually trying to find out more information about my Sharp 27" 10yr old Tv but NOTHING i could find :(... i was trying to find out if it actually had a degause feature or not know what i mean..heck i even wanted to find out what comb filter it used(2-line??) oh well i had no luck what-so-ever...

03-20-2006, 11:37 PM
i was actually trying to find out more information about my Sharp 27" 10yr old Tv but NOTHING ..this would be a good place to start http://www.samswebsite.com/-

this outfit probably has the service manual for any sharp - but you need an account - here's the list of their Sony manuals http://www.icxinyi.com/zl/105.htm

03-21-2006, 03:07 PM
In poking around a little more - this page appears to list the service manuals for 4000+ Sharp products - The page says they cost about $25 http://www.servicemanuals.net/(mbsbtz55jhr3lv45o2xrlbrx)/results.aspx?type=SM&brand=123&model= If there is a manual you require that is not listed on our web site, first make sure you searched correctly and then click the CONTACT US link at the right of the page. We will then attempt to locate the manual for you and in most cases get back to you within 24 hours.

03-26-2006, 06:00 PM
here's an interesting summation for the original question and seems to include most of the reply information in a few paragraphs Magnets
Magnets should never be put next to a colour CRT, as they may cause magnetisation of the shadow mask, which will cause incorrect colours to appear in the magnetised area - this is called a "purity" problem, because it affects the purity of one of the primary colors, with the residual magnetism causing the undesired deflection of electrons from one gun to the wrong color's phosphor patch. This can be expensive to have corrected, although it may correct itself over a few days or weeks. Most modern television sets and nearly all newer computer monitors have a built-in degaussing coil (pronounced "de-gow-sing") which upon power-up creates from standard 50 or 60 Hz household power a brief, alternating magnetic field which decays in strength to zero over the course of a few seconds. (Typically, the decay is implemented with a specialized resistor in the circuit which increases resistance with its increasing temperature as a result of the current passing through it.) The coil's interaction with the shadow mask, screen band and chassis components is the reason for the characteristic "HUMMMmmmm" noise associated with turning on many CRT-equipped displays. The decaying alternating field generated is strong enough to remove most cases of shadow mask magnetisation.
It is also possible to purchase or to build your own external degaussing coil which can aid in demagnetising older sets or in cases where the built-in coil was not effective. A soldering gun (a soldering iron will not work as it does not contain a large transformer which produces a large alternating magnetic field) may also be used to degauss a monitor by holding it up to the center of the monitor with the hot tip end facing safely AWAY from the glass (and yourself!) and while holding down the on button, slowly moving the gun in ever wider concentric circles past the edge of the monitor until the shimmering colours can no longer be seen. (To see the shimmering colors well, you may need to display a white or light colored screen.) This process may need to be repeated several times to fully remove severe magnetisation.
In extreme cases, high power magnets such as the now popular neodymium iron boron, or NIB magnets, can actually deform the shadow mask. This type of damage is considered permanent and will render the CRT mostly useless (unless a discolored area of the screen is acceptable). However, subjecting an old black and white television or monochrome (green screen, amber screen) computer monitor to magnets is generally harmless. This can be used as a demonstration tool, and children may even be encouraged to do this so that they may see the immediate and dramatic effect of a magnetic field on moving charged particles, provided they are informed to never do the same with a colour tube. http://en.wikipedia.org/wiki/Cathode_Ray_Tube

03-27-2006, 03:43 PM
My old 20" analog JVC does not have a built-in degausser I think. I cannot be sure, all I know is that I don't really hear that BYOING noise that I hear coming from most computer monitors and HDTVs these days. I hear a high-pitched noise when it turns on but I think it is just the flyback transformer warming up (the thing that emits the characteristic 16 kHz whine of all SDTVs...the whine tends to start out at a slightly lower freq and quickly work its way up to speed, when the set is first turned on).

I don't really know for sure either, though. I dunno how old this TV is, 15 to 20 years I am estimating. It has a S-Video input so it can't be THAT old. This set is at the end of its usable lifetime though (worn out tube, very VERY dark, fails any kind of calibration tests related to brightness miserably) that's one reason I need a new HDTV. :)