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anti static wrist straps

Discussion in 'Room Acoustics / Studio Design' started by bean438, Jul 11, 2005.

  1. bean438

    bean438 Guest

    where do you attach them? I have read to attach them to the pc case (unpainted), but You are also supposed to unplug the psu when working on the pc. This would eliminate the ground rendering the strap useless right?
    Would the correct way be to leave the psu plugged in BUT not connecting the main power bracket to the mobo, thus maintaining ground for the wrist strap, and protecting the mobo?
     
  2. yzfwv

    yzfwv Guest

    what I learnt in skuul.

    Wrist strap to yourself, Other end of strap to pc case, Pc case remains plugged in.

    The only reason you would unplug the case is if you're going to be working on the power supply, because there's things in there that could kill you, but poking around in the pc outside of the power supply is fine.

    It's possible to send something like thousands of volts through you to the board via static and fry it if you're not hooked up correctly. It doesn't happen all the time and you're not gaurenteed to fry the computer just by reaching in there and touching parts. It could happen though. The only thing that saves your life is, the amperage (or some other important deciding factor that I should have said instead of amperage that must have slipped my mind) Isn't high enough to kill you, let a lone do anything more than a minor shock that will annoy or irate you for a few seconds (See sliding across carpet then touching grounded metal)
     
  3. Big_D

    Big_D Well-Known Member

    DO NOT DO THIS!!!!!!!!!!!!!!!!!!!!!!!!!

    Do not leave the PSU plugged in. PSU's supply constant power to the Mobo on or off. Installing memory, expansion cards etc. with the PSU plugged in is a good way to fry those same components or the Mobo.

    You can use a grounding strap if you like and attach it to the little screw in the center of an A/C outlet but it's really not needed.

    Instead use common sense, assemble the PC in a place where static shouldn't be an issue ie. the kitchen, garage etc. Really any place without carpet. Don't wear wool or nylon (sweaters, socks) as they tend to create static electricity. Touch something grounded (stove, microwave) to disapate any charge you're carrying. Don't touch components on the contacts or chips.

    The biggest problem is in the winter when dry air creates the perfect enviornment for static electricity. At this time of year I assemble in my shop or on the kitchen table, shoes and socks off, cotton clothes and I touch something grounded before touching any components. I also tend to have my arm in contact with some part of the metal case as I work.

    Hope this helps.
     
  4. yzfwv

    yzfwv Guest

    what PC Supply company have to say about this...and it's the general consensus of several websites.

    "Whenever the casing of a computer is opened and its internal workings are exposed (to change a hard drive or add memory chips, for example), there is a danger of damaging the computer with the buildup of static electricity that is held by the human body. The internal workings of a computer, and especially the hard drive, are extremely susceptible to static electricity, which can cause considerable damage to the hard drive if it is zapped with even a small amount. Microchip damage can occur if it is exposed to static electricity as low as 10 volts, and humans are not able to perceive static electricity until it has reached about 1,500 volts. (Walking across a rug can produce a static electricity voltage of up to 12,000 volts, but static voltage is not life threatening.) So it is possible to damage a hard drive with static electricity that is not even felt by the person because it is at such a low voltage. Also, computers become increasingly susceptible to static electricity damage as more and more circuitry is built into them.
    Static electricity is caused by a process called triboelectrification. Everything around us, and including us, is made of atoms, and every atom has in its center (nucleus) positively charged protons and neutrons, which have no electrical charge. Surrounding the atom are negatively charged electrons. The protons and neutrons in an atom do not change, but the electrons can move from one atom to another. When two objects touch, they exchange electrons, which causes one object to become electrically positive and the other to become electrically negative. When an object touches another object with either an opposite or neutral charge, electrons flow. Static electricity is created when electrons move back and forth between atoms.

    To avoid zapping your components with static electricity, take precautions to ground the static electricity before touching any of the internal components of the computer. Wearing an ESD wrist strap will prevent any static electricity from damaging your computer. Another way to ground the static electricity is to touch the internal metal frame of the computer's case while the computer is plugged into an electrical socket. The static electricity will be discharged and grounded as the electrical circuit is grounded via the AC outlet. And to be on the safe side, always handle the electronic circuitry on the motherboard, video card, modem, sound card, hard drive and other internal components by any insulated, non-circuitry areas if they have them to insure that you do not send a bolt of static electricity coursing through it.

    An important exception to this rule is when working inside monitors. You should not ground yourself before working inside a monitor. Monitors store electricity in capacitors, and by grounding yourself you will provide a conduit for the voltage to discharge through your body."

    This is for working on a PC and doing stuff like changing the memory or replacing a drive....this it what I was talking about...
     
  5. bean438

    bean438 Guest

    Big_D I understand that power is constant to the mobo even when the PSU is "off".
    I asked in my post if leaving the PSU plugged in but NOT connected to the mobo would be fine.
    This way I still am connected to ground but not indangering the mobo.
    Simply unplugging evrything and then attaching the strap makes no sense as you are not connected to ground.
    However I have read that the strap does not have to connect you to ground. It just simply has to give the static somewhere to go.
     
  6. Big_D

    Big_D Well-Known Member

    Yes, it would be fine to do as you suggested. My point was that you can do the same by attaching the griund strap to the little screw in the center of your outlet. This is ground also and would prevent damage to the PSU if a screw should fall into it during assembly.

    Yes and no. Ground (earth) is not just present in an electrical outlet, it is all around you. Electrical appliances are grounded, one of the reasons I said you could touch one to discharge static. But have you ever touched a door knob and gotten a shock, this is ESD and it happens because you are earthing yourself. Electricity will always follow the path of least resistance. The object is to discharge the static buildup anywhere but your components.

    If you feel the need for a static strap by all means use one. I've been building and repairing PC's (thousands of them) in my job for 15 years and have never blown out a single component due to ESD yet I have never worn a static strap. It's all about discharging the static one way or another.

    Good Luck!
     
  7. Randyman...

    Randyman... Well-Known Member

    I'm in agreement with Big D. I never work on my PC with the PS plugged in (just asking for some kind of trouble IMO). I, too, never use ESD bracelets, and I have not damaged any components this way (not as much experience as Big D, but I've done lots of my own PC work).

    As long as you are not "scooting" across the carpet floor with your socks on, you should be fine. All I usually do is touch the case, and the case will then take the static charge to ground. Once you release this initial charge, you should be OK unless you go back to "scooting across the floor with your socks on" :wink: . Also of note - Static Electricity is more prominent in dry climates. I live in a very humid area, so YMMV...

    :cool:
     
  8. Big_D

    Big_D Well-Known Member

    Changing memory and expansion cards is exactly what I'm talking about. I can't think of a single mobo manual written in the last 5 years that suggests leaving the PSU plugged in to install components as a matter of fact they all tell you to unplug it. They do this because memory slots are hot (have electricity flowing to them) and installing memory into a live slot is a sure way to destroy your memory and mobo as well. That's why mobos have that little light (RAM LED) so you know when power is on at the DIMM slots.

    Here's a qoute from the Gigabyte K8NS manual. "When the RAM LED is on do not install/remove DIMM from socket". Power is present at the DIMM slots whenever it is plugged in.

    As I told Bean I have never destroyed a component with ESD but I have wrecked a few by dropping screws onto boards that were plugged in.

    I know all about preventing ESD, my point was don't plug your PSU in. BTW static straps are not as effective as you might think, their real advantage is the constant connection to ground. Touching ground with bare skin is far more effective.

    The last paragraph about monitors is only half right. It is correct in saying that you shouldn't ground yourself to the monitor but fails to mention grounding the fly back transformer, the place where all of those cap voltages become lethal.

    If you like plugging in go ahead. I just don't want people to get the wrong impression that it is necessary or even correct to do so.
     
  9. Drizzt

    Drizzt Guest

    I think with the quality of components these days ESD is of very minor concern. I have worked in a PC support environment for 4 years and on PC's in general for 12 and have never fried anytihng with ESD.

    COurse i have changed memeory many times on a PC that is still plugged in but not on but as a general practice it's best to unplug.
     
  10. BladeSG

    BladeSG Guest

    I too have built countless DAW's and general PC's too and have never fried a single component. I do not own a strap and have never used one. There is no harm in leaving the power lead connected to the PSU but with the switch on the back of it TURNED OFF. This way the chassis is still connected to earth. I'll never get inside a PC with the PSU live or switched to the ON position. On modern motherboards if you can see a lit LED on that motherboard it means the PSU is live, turn it off, then touch the chassis of the PC before touching any of the components inside.

    And yes I find that the kitchen table makes for the best workshop.
     

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