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Thread: "The Shocking Truth", Apple's internal video about electrostatic discharge damage

  1. #1
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    Default "The Shocking Truth", Apple's internal video about electrostatic discharge damage

    Gang,

    The other night I dug out my pirated DVD of some of Apple's internal videos and re-watched the one that explains how semiconductors are damaged by static electricity (sometimes without anything coming into contact with the board or component). It's on Youtube:

    (Parts 1 through 4)

    http://www.youtube.com/watch?v=4WHbcd4NGJQ

    http://www.youtube.com/watch?v=AT2bhYLgFiM

    http://www.youtube.com/watch?v=8DXjx2k1kYk

    http://www.youtube.com/watch?v=ACstwfL4x84

    The video got me to wondering. Actually, I have three cards that have been sitting next to my TV for years, waiting to be installed. The video said that they should be in a bag or in a computer to be protected, so I'm probably screwed anyway. But I was just wondering if anybody knew if they could be damaged by the field that the TV generates when it first turns on. Anybody?

    Thanks,
    Sean

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    Alright, I learned some things from this video. Very well worth watching.
    Last edited by lutiana; April 21st, 2010 at 09:42 PM.

    IBM 5160 - 360k, 1.44Mb Floppies, NEC V20, 8087-3, 45MB MFM Hard Drive, Vega 7 Graphics, IBM 5154 Monitor running MS-DOS 5.00
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  3. #3

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    Hi
    Yes, putting it in front or close to a tube type color TV can
    damage by static electricity.
    One thing he said was a little incorrect. Being on a board
    does offer some protection but can increase the chance of
    being damaged. Three factors:
    1. The capacitance of the line or trace: The amount of charge,
    such as from coming near a non-conducting surface with a charge
    on it is reduced by a larger trace.
    2. Alternate path to ground: On a board most sensitive inputs
    are also connected to output drives. These are usually a diode
    voltage away from the ground and power rails.
    3. Adjacent trace sheilding: A static field gets didstributed across
    many traces.
    The transistors he was blowing up were unprotected gate VFETs.
    They are quite easily damaged. At a place where I worked, over
    time, the soldering irons had lost their ground pins ( I suspect
    plugging then into cheap extention cords ). They used these to
    solder in a bunch of VFETs. Almost 80% were blown!
    The other part that you'll find is very sensitive to static is the
    CMOS analog gates. Some of the numbers I recall are 4051 and 4052.
    These need extra careful handling.
    When I was at Intel ( years ago ), a work was carrying a EPROM
    at arms length, pins facing away and holding the case.
    I asked if she was trying to see if she could destroy the chip.
    She said that she'd just seen a movie on how static could damage
    parts and was being especially careful to not damage that part.
    I was shocked. I explained to her( although I doubt it soaked in )
    that the way she was carrying the part was just about as bad
    as could possibly be done.
    If as a last resort, you closed hand is a Faraday shield. I told
    her that if she couldn't find a proper protective surface to put
    it in or on, she should put it in her closed hand.
    She didn't get it. What she got from the movie was "Don't touch
    the leads".
    Dwight

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    Quote Originally Posted by Floppies_only View Post
    Gang,

    The other night I dug out my pirated DVD of some of Apple's internal videos ... It's on Youtube:

    (Parts 1 through 4)
    Somebody asked me if I posted pirated videos to YouTube. I didn't. I just posted the links to them here.

    Sean

  5. #5

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    Nice vid, learned a couple new things. I had no idea that holes in a antistatic bag made the bag useless.

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    Quote Originally Posted by Floppies_only View Post
    Somebody asked me if I posted pirated videos to YouTube. I didn't. I just posted the links to them here.

    Sean
    Yeah, that was me, it just sounded kind of dangerous. But I realized afterwards that it was just a link to what someone else posted. Thanks for it, as I said I learned a lot from it actually.

    IBM 5160 - 360k, 1.44Mb Floppies, NEC V20, 8087-3, 45MB MFM Hard Drive, Vega 7 Graphics, IBM 5154 Monitor running MS-DOS 5.00
    IBM PCJr Model 48360 640kb RAM, NEC V20,, jrIDE Side Cart, 360kb Floppy drives running MS-DOS 5.00
    Evergreen Am5x86-133 64Mb Ram, 8gb HDD, SB16 in a modified ATX case running IBM PC-DOS 7.10

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    Interesting - this has convinced me to use my IBM wriststrap kit that I recently got on a regular basis.

    Edit: One thing I don't get though - the rubber mat is supposed to be grounded to the wall's "earth ground", right? How do you do that? Mine has two snaps for hooking it up to your wriststrap, and then the wriststrap has an alligator clip for clipping to the chassis or some such. As far as I can tell that gets you no *proper* ground....?
    More commonly known as "Yushatak" - www.yushatak.com
    Focused on 486 and Pentium Machines
    I collect All-In-One PCs and Keyboard PCs, especially Compaq.

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    A true anti-static rubber mat should be laced with a wire mesh on the inside of it, and that all connects to a wire, and then you ground that onto an outlet. that's what we used back in the days of Zeos anyway.

  9. #9

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    Dell (I temporary worked there in the assembly line for a few months ..like..10 years ago) had their folks stand on those mats with an ESD band on. It was one of the very few things I was impressed with there. It would actually sound a loud beep if you weren't grounded to the mat or stepped off of it. It was a good thing as most of the kids working back there don't know anything about computer or ESD, all the parts are made to snap into place with plastic to ease the use for non-technical folks.
    Looking to acquire: IBM 5100, Altair 8800

  10. #10
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    I guess mine is just designed for chassis-grounding then.
    More commonly known as "Yushatak" - www.yushatak.com
    Focused on 486 and Pentium Machines
    I collect All-In-One PCs and Keyboard PCs, especially Compaq.

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