magnetic damage to TV tubes....

brettw22
brettw22 Posts: 7,623
edited February 2024 in Clubhouse Archives
OK.........how LONG does it take for a tube to be exposed to a magnet to permanently damage it?

I had a cs1000p on top of my screen for all of 10 minutes and my screen has all of a sudden gone wrong in the upper corners. As soon as I saw the discoloration in the corners I took it down. Prior to the 1000 being on the set, the blue screen (if a DVD's not playing) was solid and has been for 5 years. Not any more.......

I've degaussed repeatedly and the discoloration keeps creeping back......Am I just totally screwed?
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Post edited by RyanC_Masimo on
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  • Jstas
    Jstas Posts: 14,842
    edited January 2003
    Have you tried turning it off and leaving it off for a while? Like a few days? That happened to a computer monitor I had once. So I turned it off, unplugged it and put it aside. A few days later I turned it back on to see if I could figure out what happened and it wasn't there anymore.

    I don't know exactly what happens but since the Cathode Ray gun is basically an electron gun, the magnet may have polarized the phosphors on the screen that the electrons make glow. If they are polarized opposite of what they are, they don't absorb but reflect. Consequently you get dead spots on the screen. I suppose that leaving it off lets the polarized charge dissapate so it returns to normal.
    Expert Moron Extraordinaire

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  • F1nut
    F1nut Posts: 50,760
    edited January 2003
    I think and I say think, that a TV tech can fix it.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

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  • brettw22
    brettw22 Posts: 7,623
    edited January 2003
    10:07pm........TV's off for a day or two.

    Can at least try that...........my GOD, what the hell am I going to do in the meantime.......:lol:

    Oh ya........the thing that would totally suck **** is if this is perma-damaged because it's a 40" Mitsubishi Tube that they don't make any more. I can't even imagine how much the cost of the tube would be on the thing, if it's even available........
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  • madmax
    madmax Posts: 12,434
    edited January 2003
    There is degaussing that is done when the set is turned on but it is minimal. A tv tech can use a big round coil of wire which plugs into the wall to (hopefully) get rid of it. When I first got my 36" monitor it had this problem. It seemed much more sensitive than most of the ones I knew of. Rather than going through the hassle of getting a tech out here I used a huge subwoofer magnet to do the same thing but it took me forever to get it right. I don't suggest doing it that way. Call someone. It can be fixed. If they don't seem to get it right at first make sure they keep trying.
    Good luck!
    madmax
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
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  • brettw22
    brettw22 Posts: 7,623
    edited January 2003
    Wouldn't the subwoofer magnet be doing DAMAGE to the tube rather than helping it? The TV that I have has a manual Degaus button on the front of it that I can click on, so I've done that a few times. As of now, the set is turned off, and completely unplugged until at LEAST tomorrow night. I'm gonna try to let it get rid of everything like Jstas suggested. If that doesn't work, I suppose a tech is about all I can do.

    There is NO WAY IN HELL that I'm taking it to them. The **** weighs about 240 pounds..........
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  • madmax
    madmax Posts: 12,434
    edited January 2003
    Don't try it because you could if you didn't know how to manually degauss a tube. The ring they use to do it is basicly an electromagnet.
    madmax
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
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  • HBombToo
    HBombToo Posts: 5,256
    edited January 2003
    Its a very tricky resolution you guys are talking about here. I would say if you don't have experience digging into the guts of a TV then don't because its very dangerous.

    my 2c only

    HBomb
    ***WAREMTAE***
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  • TonyPTX
    TonyPTX Posts: 545
    edited January 2003
    Originally posted by brettw22
    As of now, the set is turned off, and completely unplugged until at LEAST tomorrow night. I'm gonna try to let it get rid of everything like Jstas suggested. If that doesn't work, I suppose a tech is about all I can do.

    Let us know how it turns out. I got a 27" tube that has the upper left corner discolored. Only really visable when you have a solid color on the screen like the VCR or receiver setup screens.
    Damn....8 lines...I've gotta put my sig on a diet now....
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  • Jstas
    Jstas Posts: 14,842
    edited January 2003
    There isn't any real reason to go digging in a TV to fix this kind of problem. It affects things inside the glass tube so even if you broke open the box to get a gander inside, you wouldn't be able to see inside the glass tube anyway.

    But yes, inside a TV, there are several fun things like high current capacitors and a couple of transformers for stepping voltage. A TV's ray gun for beaming electrons at the tube requires something like 12,000 volts. That may be a high number but I know the amount of power being stepped by the transformers is more than enough to kill you. So no poking around inside a TV. Especially not when its plugged in.
    Expert Moron Extraordinaire

    You're just jealous 'cause the voices don't talk to you!
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  • rskarvan
    rskarvan Posts: 2,374
    edited January 2003
    One time, quite a while ago, I set one of the generic 6-1/2" drivers from my M10's next to the monitor while surfing on the polk website for replacement drivers. Sure enough, the speaker magnet screwed up my monitor. The degauss wasn't strong enough to fix it. So, I very carefully used the speaker to fix the problem with the monitor. It was ugly and scarey... but, with a little fiddling around, I got it back to normal and its been fine ever since. Scarey predicament.

    I felt soooooo stupid for ALMOST ruining my computer monitor.

    Sigh.
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  • brettw22
    brettw22 Posts: 7,623
    edited January 2003
    Well, got this fixed through a few ways...........

    About 2 weeks ago I was reading through my TV's manual and read about a switch on the back to indicate whether the set was facing North, South, East, or West. Apparently for some of the larger tubes, they're more sensitive to magnetic pull, so I made the change and all appeared fine for a while...........until I put that cs1000p on top.

    I left the TV off for a day and a half, unplugged, but the discoloration still remained, though not *quite* as bad as it was. I had forgot that I'd messed with the directional switching, and switched it back to what it was before (wrong according to the direction it's facing) and the probem seems to be pretty much gone.

    What a HUGE relief to have it back to normal. On normal video, be it cable or DVD, the picture appears ok. It's on the blue programming screen that I can't tell if there's any purple haze spread around. It's definitely not bad in the corners, but now i think that i'm just staring too much at this screen so I think that my eyes are putting stuff there.

    Just wanted to let y'all know it was fixed.........Thank GOD I don't have to go out and try to buy a TV that would be comprable to my 40" tube. I love this thing...............
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  • Tour2ma
    Tour2ma Posts: 10,177
    edited January 2003
    For future reference:
    http://www.anatekcorp.com/degaussi.htm

    also the Google search that led me to the above site:
    http://search.earthlink.net/search?site=earthlink-ws&q=degaussing
    ,,, but it may be earthlink specific.

    Just use whatever engine you prefer to search "degaussing", only about 14,000 hits...

    My SRS's have gotten to my Toshiba. I have an old electromag bulk tape eraser I think I'll give a crack at it. Will practice on the old Proton first. The SRS's ate it alive about 8 years ago.

    Also will go though ancient issues of Stereo Review I still have. I remember an article on building you own shields.
    More later,
    Tour...
    Vox Copuli
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