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  1. #1
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    Question Magnets on computers

    Please don't laugh at me folks, but a friend of mine and I have had something of a minor debate over magnets on computers. For example, I have a fancy new high-speed tower model with all the whistles and buzzers in the world, but I have resisted the urge to use the removable side panel to post reminders and the like to myself with anything but tape. I prefer using what some folks call "refrigerator magnets" but I was told years ago that magnets and computers are NOT FRIENDS, and they should not be put there. My friend says that is not true, at least not today, but he says it may have been at one time.

    This is the trivial question for the day, perhaps even for the week or month, but can anyone out there tell this NONtechie intermediate computer user if he can safely use small magnets to put ever-changing notes and temporary reminders to himself on the side panel of his shiny new Dell laptop, please? I would like to for the sake of maybe getting myself organized (hopefully), but not if it will do harm to my expensive new toy as I was told. Thanks.

    David E. Cann

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    I think only floppy disks were ever really vulnerable to corruption by small magnets. (But you said laptop in the second paragraph; you meant desktop, right?)

    Bruce

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    5 Star Lounger RussB's Avatar
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    Do not put strong magnets too close to your HDD, but...
    I use them all the time on my tower and have for years. I have never had problem with memory or drives, did lose a Video board once when a fan died and had to replace a power supply. It is very unlikely that the magnets caused either problem.
    I even have a couple of rare earth magnets that have very strong magnetic fields. But I do not use floppy disks or other magnetic media any longer either.
    It is this old magnetic media and tube style video monitors that magnets can disrupt or even destroy.
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    Bruce,

    Woops! Yes indeed, it is definitely a desktop, despite what I said above. A Dell XPS tower model if that matters with anything. This is no big deal really, but I just got to talking about it with a friend and we can't agree on whether using magnets on the side panel would risk damaging it or not. That side panel is kind of my small bulletin board for notes, but I currently use tape.

    David E. Cann

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    David,

    you can breath easily: there will be no measurable effect with the fridge magnets. You can use them without a worry, well except for worrying about the paint on the case!

    Fridge magnets are very weak and the field is highly unlikely to be able to penetrate the metal case. The metal case is designed to shield external equipment from electromagnetic hazards generated inside the computer. This shielding is also effective at reducing external magnetic fields from entering the machine too. Even if an external field entered the case (and it would be weaker by then), current can only be induced into a conductor if the magnetic field is alternating. A static field, such as that surrounding a static magnet, does not induce current into a conductor. Only during the time the magnet approaches or is removed from the case will the field change and hence be able to induce currents. Even then, any field than manages to escape into the case will be very low and the noise currents induced will be so small as to make no practical difference.

    Many years ago, I had the opportunity to work on a specialist machine that was designed for emergency erasure of magnetic tapes. We had to dump such huge amount of energy into the tightly surrounding coils that a screwdriver left on the bench about 10cm away from the coil was physically moved by the magnetic pulse. The field from the fridge magnet will be many thousands (if not millions) of times smaller.

    You may or may not be aware that inside a hard drive enclosure, there are a pair of incredibly strong rare-earth magnets. If you ever get the chance to crack open and disassemble a hard drive, you need to be especially careful with your fingers as the rare earth magnets are so strong that they can easily cause injury by crushing the skin etc. Yes, they are surrounded by u-metal to dampen down the field outside of the hard drive enclosure, but I expect there will be a much greater field inside the case generated by leakage from these rare earth magnets than the tiny field generated by a fridge magnet on the outside of the case.

    Hope that sets your mind at rest.
    Last edited by Tinto Tech; 2012-08-23 at 17:26. Reason: grammar
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    Quote Originally Posted by RussB View Post
    Do not put strong magnets too close to your HDD, but...
    I use them all the time on my tower and have for years. I have never had problem with memory or drives, did lose a Video board once when a fan died and had to replace a power supply. It is very unlikely that the magnets caused either problem.
    I even have a couple of rare earth magnets that have very strong magnetic fields. But I do not use floppy disks or other magnetic media any longer either.
    It is this old magnetic media and tube style video monitors that magnets can disrupt or even destroy.
    RussB,

    These are nothing but common garden variety little magnets like some people (like my wife) might stick the grandkids' picture onto the refrigerator door. Nothing particularly strong or very large.

    David E. Cann

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    Plutonium Lounger Medico's Avatar
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    I have an experience with magnets on PC's to relate. See this thread for a more detailed post.

    Basically my granddaughter had a problem with her laptop. It kept going to sleep intermittently when ever she started typing. It was doing very strange things that would not occur when I was using it. We found she was wearing a magnetic bracelet on he right wrist (one of those things used to help with migraines). The problem mysteriously went away when she removed the bracelet. We never did know exactly what the bracelet was affecting, but lesson learned.
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    Tinto Tech,

    I thank you for the information, and a very interesting reply. It does indeed make me feel better, and now I will use a few (though very few) small magnets rather than the tape. I just wish I had listened to people decades ago when I went into the Marine Corps (1962) who told me to go into computers (was called data processing then, I believe), I would sure know a lot more now than I do and not have to ask dumb questions like I just asked, but that is an entirely different topic for another time. Thank you again.

    David E. Cann

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    Quote Originally Posted by Medico View Post
    I have an experience with magnets on PC's to relate. See this thread for a more detailed post.

    Basically my granddaughter had a problem with her laptop. It kept going to sleep intermittently when ever she started typing. It was doing very strange things that would not occur when I was using it. We found she was wearing a magnetic bracelet on he right wrist (one of those things used to help with migraines). The problem mysteriously went away when she removed the bracelet. We never did know exactly what the bracelet was affecting, but lesson learned.
    Well, after being convinced by the others there was nothing to worry about, now I am back to worrying again and keeping the magnets on the fridge. <sigh> :-(

    David E. Cann

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    Plutonium Lounger Medico's Avatar
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    You have to remember this was a laptop PC and the magnet was being held just above the area to the right of the touchpad. I have no idea what was being affected, but I spent hours trying to figure this little quirk out only to discover my granddaughter had just started using the bracelet. Who knew!
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    @ Ted, I didn't see your original post, otherwise would have made a note in that thread. Unfortunately, it's a well known issue on Dell Inspiron 15 machines. They have a small magnetic reed switch which is normally activated by closing the lid (magnet located in the lid), triggering a sleep mode. Your grand-daughter's bracelet would have been strong enough to activate the reed switch triggering the laptop to enter sleep. See this you tube video for a demonstration of a similar effect on a Dell N150 laptop. It's a reed switch and magnet in the case and lid.

    @decann: don't worry, unless you have a reed switch activating sleep in a laptop. Since this is a desktop, it won't be a problem.

    /Edit : Actually it illustrates the energy levels involved. The bracelet will have a similar order of magnitude field as a fridge magnet and it can only operate a tiny sliver of steel in a reed switch from a few millimeters away. Imagine the amount of energy required to move a large screwdriver about 10cm away and that's the energy levels we had to deliver to erase the tapes.
    Last edited by Tinto Tech; 2012-08-23 at 18:24. Reason: extra observation on energy levels
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    Medico (2012-08-23)

  13. #12
    Plutonium Lounger Medico's Avatar
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    You do not know how much hair I lost over that one. Thank you. I passed along info to my grand daughter.
    BACKUP...BACKUP...BACKUP
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  14. #13
    Super Moderator jwitalka's Avatar
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    I had a friend who lost his hard drive partition when he used a refrigerator magnet on the case right next to where the hard drive was mounted. If you want to pot notes on your PC, Post It notes would be a better option.

    Jerry

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