uhoh...exposed my MBP to "strong magnetic field"

Discussion in 'MacBook Pro' started by flalaw, Dec 8, 2006.

  1. flalaw macrumors regular

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    #1
    I kinda messed up today. Without thinking I set my MBP on my Logitech Z-5500 subwoofer and left it there for a good 15 minutes or so. Both my computer and the speakers were on. I remember reading a warning on the subwoofer that said it has strong magnets in it and to not put any electronics within 2 feet of it.

    Are there any potential problems I might face, or am I in the clear? I feel like there's some screen distortion to the left and right, as if the image is bent, but this might be completely in my head.
     
  2. iW00t macrumors 68040

    iW00t

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    #2
    Better send it to an Applecentre, but don't say you put it close to a magnet :mad:
     
  3. CanadaRAM macrumors G5

    CanadaRAM

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    #3
    Shouldn't be any magnetic screen distortion on an LCD screen unless my guess is wrong (CRT monitors, that's a different story).

    The thing to do is to boot from your OSX DVD and run a Repair Disk on you hard drive. If it passes OK, then you're pretty much in the cleat. It would take a very strong magnetic field to do much to the machine.
     
  4. CDailey macrumors regular

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    #4

    The magnet on the Z5500 sub is pretty big. It's a 10" sub. The manual for the thing says to keep it at least 2 feet away from TVs and such. And they mean it. I had my sub under my TV once with about 18 inches inbetween and it caused discoloration on the bottom right of my tv screen. :eek:
     
  5. flalaw thread starter macrumors regular

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    #5
    did you have an lcd or crt?
     
  6. CanadaRAM macrumors G5

    CanadaRAM

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    #6
    The point is: <simplistic description of cool technologies follows>

    A TV or anything with a Cathode Ray Tube uses a stream of electons shot from one or three guns (cathodes), that are deflected by magnetic coils, to sequentially paint phosphor dots on a glass screen, after passing thru a metal grid. A magnetic field will certainly temporarily deflect the photons, causing image distortion, and can also permanently magnetize the internal metal components, including the shadow mask or grid, causing permanent distortion. The "degauss' function on a monitor *(the one that makes the really cool Star-Trek noise) is there to de-magnetize small amounts of distortion from this cause.

    A LCD monitor is totally different - no guns, no electron screens, no magnets and no ferrometallic bits inside. It works by shining light from a florescent bulb, through a series of colour filters, and having the light blocked or allowed out by tiny cells of a liquid crystal compound, which twists into different shapes depending on the heat applied to it. Each cell, or pixel, of a LCD is controlled by a transistor printed onto a layer of glass .. the screen then is a glass sandwich with the transistors and liquid crystal elements in the middle.

    Soooo... when it comes to Liquid Crystal Displays (LCDs) they are in no way comparable to CRT's (Cathode Ray Tubes)
     
  7. flalaw thread starter macrumors regular

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    #7
    my screen is fine and i guess it was all just in my head. no problems after verifying w/ disc utility, so hopefully i'm in the clear.
     
  8. tjcampbell macrumors 6502a

    tjcampbell

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    #8
    I have the same sub, but it's on a rolling sort of side of table with a shelf for my xbox 360. I have a ceiling mounted projector so when I want to watch something on it through my MBP I have to set it on the top of the side table so I can wire the optical into the speakers and run the cable to the ceiling. I watch at least five movies a week like this with my MBP sitting above the sub the entire time. I have never seen a problem, nor even thought that this would be an issue. I really wouldn't worry about it.
     
  9. flalaw thread starter macrumors regular

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  10. princealfie macrumors 68030

    princealfie

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    #10
    Well the worst that could happen is that your MBP gets transported to the next dimension (not Dell dimension btw).
     
  11. cardiac dave macrumors regular

    cardiac dave

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    #11
    it won't affect the LCD, but it could have done some damage to the hard drive.

    Run a good disk checking utility - it it looks good, you got lucky.

    I had an incident last year with a brand new ibook, where I accidentally let the iSight magnetic base (for the iMac) plop right down below the keyboard and killed the hard drive. The OS X DVD disk utility wouldn't even recognize the hard drive.
     
  12. flalaw thread starter macrumors regular

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    #12
    Is the standard disc utility in the utilities folder okay? no problems after i hit "verify"
     
  13. CDailey macrumors regular

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    #13
    Thanks for the quick lesson. I know the difference though. ;) I didn't know a magnet couldn't affect it though. I was also worried about his hard drive - the main reason for my post. I just threw in the bit about the TV as an example as to how strong the magnet is.
     
  14. Sesshi macrumors G3

    Sesshi

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    #14
    If it works normally and the HDD checks out, you should be in the clear. I'm frequently asked to sort out computer setup issues at the companies I work for (where it is usually damage control for whatever clueless IT support moron they have working for them who just blames problems on kit) and it is surprising how many people have subs sitting on or next to minitower PC's, and they do still seem to work. However while satellites may be shielded, subs are usually not.
     
  15. cardiac dave macrumors regular

    cardiac dave

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    #15
    I would think that if 1) the computer still appears to work fine, and 2) using the disc util - the SMART status is OK, or VERIFIED then you're golden.

    In my extreme example, it was basically a strong magnet, stuck almost directly to the hard drive. In your case, there was still a good distance between the actual sub magnet, and the hard drive... the magnetic field drops exponentially with distance... enough to distort a CRT/TV but likely not enough to damage a hard drive.
     
  16. Chaszmyr macrumors 601

    Chaszmyr

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    #16
    I believe Logitech does shield their subs, though they still produce a magnetic field. In a laptop such as yours, the only serious problem post-exposure would be the hard drive, but it sounds like the hard drive is still in good shape so you should be fine.
     
  17. sycho macrumors 6502a

    sycho

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    #17
    A stationary magnetic field will not harm a magnetic hard disk. Think about the magnets in the hard drive, they are small, but pound for pound they are alot, and I mean ALOT, stronger then the motor on a speaker. Now, if the magnetic field was moving, it might be a different story, but even then, it is very hard to affect a hard drive.:)
     
  18. flalaw thread starter macrumors regular

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    #18
    would it potentially be a problem if i put my printer on the sub? i've got one of those free w/ rebate all in one HPs
     
  19. skippy911 macrumors regular

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    #19
    Why not buy a stand and stop putting all you crap ontop of your sub? Put the sub in your car where it belongs.
     
  20. flalaw thread starter macrumors regular

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    #20
    space managment is pretty important to me, as is music. might as well use the space if i've got it, and no point in getting a stand if there's no danger to the equipment, right?
     
  21. 840quadra Moderator

    840quadra

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    #21
    If your system has Mag Safe, it has a strong magnet inside the case. If your system is an older iBook, you had a strong magnet only inches away from your hard drive, that was used to activate the latch cover.

    You will need lots of gauss (measurement of magnetic fields) before you will damage a hard drive in a mere 15 minutes. Your system is fine, and so is your data!
     

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