Computer turns off from static shock

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Old 01-15-13, 11:11 PM
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Computer turns off from static shock

Well, this has never happened to me before. I was connecting my digital camera to my computer via USB cable to export photos to my hard drive. When I touched the cable to the USB port, I was holding the camera with the other hand. I felt a shock where I was holding the camera. Then the monitor screen goes black and the PC appears to log off.

I shut it down for a while then restarted in safe mode,then restarted normally. Everything seems to be ok. This seemed highly irregular. So I did some reading and other people describe PC's shutting down from ESD (static shock) A few were unable to start their computers afterwards.

I always knew that ESD was harmful when working with the components inside the PC. But you have to be careful not to shock the outside of the case also. I almost always remember to discharge my static before touching the PC. Sometimes the shock is quite painful.

Near my workstation there is a ceiling fan with a metal pull-chain. Is this good enough for bleeding off my static electricity?

I heard some people use a little extra wire to install additional grounding points for the case and mother board. But how do you do this? Where is the additional wire attached?

In addition, would it be safer to press computer on/off switch with wood or plastic object instead of bare finger?
 
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Old 01-16-13, 02:44 AM
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You don't mention what type of computer you have and whether it is a laptop or a desktop. There are different ways to ground yourself safely before proceeding. On a laptop like a Dell laptop for instance touch the back of the screen as you can safely ground out any ESD on the back of the screen without hurting any of the components inside. On a desktop select a metal area of the case to touch on the top as that shouldn't hurt the desktop computer.

You can also buy either disposable or reusable grounding straps to ground yourself to say an electrical plug. The disposable grounding straps are cheaper and can actually be reused over and over again with care.

You really shouldn't be having that much static electricity though especially not where you live however I do know that Arizona does have some really bad cold spells. Up further north here in Maryland almost everybody has a whole house humidifier attached to their furnace. The humidifier only runs when the air is too dry. So if you haven't done so already and you are not renting your premises then I suggest you get a humidifier installed on your furnace. You will feel better and your computer will not have any more problems with ESD.

If you are renting or budget doesn't allow then you can buy portable humidifiers and ones with humidistats that will shut the humidifier off when the air has enough moisture. After all too much moisture in the air is bad for your health and isn't good for other things including your computer so make sure it has a humidistat. Another alternative would be a vaporizer and if you already have one then you are all set. Just make sure not to run the vaporizer too long or you will get mold in your house. I would say no longer than 30 minutes for a vaporizer and that should add enough moisture in the air to prevent ESD. Also depending on the weather you might not need to add any moisture to the air. There looks to be a great article on About.com that I glanced through that gives you tips on buying a portable humidifier here is the link Before You Buy a Room Humidifier - Humidifier Buying Tips .

As you will see there are many different portable humidifiers and some are better than others. Just as there are many different portable humidifiers there are many different humidifiers for a furnace too with some being better. If installed on a furnace it isn't real hard to install but I really suggest a professional to come out and install it as that way hopefully you will get the very best unit.
 
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Old 01-16-13, 06:32 AM
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I have a home built desktop PC. Right now we are having a spell of cold, dry weather in Arizona. I am not comfortable touching my computer case. That grounding strap you mentioned at the electrical plug interests me. I have a couple small oriental rugs around the PC area. I will probably move those to another room in the house.

But I would like to learn how to add extra grounding wire for the motherboard and case itself if anyone knows how. Thanks
 

Last edited by bluesbreaker; 01-16-13 at 06:59 AM.
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Old 01-16-13, 06:36 AM
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Provided the fan is properly grounded, you can use the fan casing or chain to ground yourself. If I'm particularly concerned about grounding myself, I will touch the faceplate screws on a grounded wall outlet or a water pipe. In fact, many antiESD straps have a wire that you connect to this screw.
 
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Old 01-16-13, 06:52 AM
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I've had this happen a few times with my primary workstation, a hand-built machine in a rackmount enclosure bolted into a two-post rack in my office. I simply ground myself on the rack now before I touch the computer. And like you my experiences were based around plugging things into the USB port.

Though now that I think about it, when I'd experience shock, the computer wouldn't just spontaneously power off, but would trigger the shutdown sequence as if I had pressed the power button. That makes me wonder if the 5V for the USB is too closely tied into the power button, so the shock on mine might be triggering the momentary for soft-power which triggers an ACPI event, which causes Windows to shut down the computer thinking that it's been instructed to.
 
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Old 01-16-13, 01:06 PM
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What about this method? Just plug an old cell phone charger into the wall outlet and touch the metal plug peridocially? This would be the easiest thing for me. I have a wall outlet within arm's reach. I don't have to stretch or reach to bleed off static charges. And I don't have to be wrist strapped to the wall outlet.
 
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Old 01-16-13, 01:22 PM
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Cell phone chargers aren't hooked to ground, just hot and neutral. Granted, neutral is normally hooked to ground in the panel...

The case of the computer should be safe because case itself is hooked to ground through the inside of the power supply into the power connector.
 
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Old 01-16-13, 03:03 PM
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The motherboard is always grounded inside the case because it is always connected in the inside to the metal part of the case. So all you have to do is touch the outside of the case to get rid of ESD. As for the rugs I wouldn't move them and I would keep them where they are. What I might do particularly if I had the same problem that you have is buy a rubber mat for under the chair that I was sitting at. You can find office chair mats at about any office supply store here is just one example at Staples Staples« Flat Pile Carpet Chairmat, Standard Lip, 36'' x 48'' | Staples« . I am not saying buy there as you might find what you need cheaper somewhere else that should hold up over time. Basically the principal is the same as wearing rubber soled shoes if you were working on electricity. Using moisture in the air helps cut down on the static electricity and is helpful as far as sinus conditions are concerned which is why I mentioned it helping you too.

The ad at Staples says this isn't anti-static and it doesn't look like it is made of rubber but they make mats just that size to help cut down on static and even that mat may help as it would be a barrier between your carpet and you. Just make sure you touch something metal to be absolutely certain.
 
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Old 01-16-13, 09:00 PM
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You wouldn't have to use a wrist strap. You could just take an 18 gauge stranded wire (so its easily flexible) and crimp on a spade connector. Then you can attach the wire to the center screw on the wall outlet. Strip insulation from the other end of the wire and tape it(or some other mounting method) to the desk where you can reach over and touch this grounding wire.
 
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Old 01-16-13, 09:49 PM
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Ok then. I'll probably alternate between the wall outlet screw and the case. But the wall outlet is so close to my office chair, I don't even need to extend a wire. Can't I just touch the screw with my finger? My wall outlet face plate only has the one center mounting screw.....is this ok?

As for the touching the case to bleed off ESD, I'm still not certain of the best place to touch the case. My case is black painted metal. Even the rear of the case is mostly black painted with a small strip of metal. What about that circular 'grill' that shields the power supply fan? Thanks
 
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Old 01-17-13, 03:38 AM
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If your wall outlet is that close then certainly all you would need to do it touch the screw. As for the case being painted that probably wouldn't be an issue as upstairs where I have a desktop I built for watching tv I have touched its case and received a mild shock from static electricity. For your own piece of mind try it both ways and see how it works for you.

I knew they had anti-static floor mats that you could buy and I was right. Here is a link from Office Depot Plastic Chair Mats and Office Floor Mats at Office Depot . Again I am not saying buy there as there may be cheaper alternatives somewhere else. At least now you have several options open to you in what you can do to protect your computer. Also consider power surges as they do quite a good deal of damage too. We have a whole house surge protector installed in our electric panel that seems to have protected our electronics. I would either do that or just unplug things or turn your power strips off during a storm.
 
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Old 01-17-13, 06:10 AM
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Thanks for all the input. Yes, I am a big believer in surge protectors. I have ALL my electronics plugged in to good quality ones. I'll look into the anti-static mat. I forgot to ask before. Last question.

Whe discharging ESD on the computer case...............PC on or off........power supply on or off........does it matter?
 

Last edited by bluesbreaker; 01-17-13 at 07:53 AM.
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Old 01-17-13, 12:39 PM
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In my opinion I don't think it matters it might be better to keep it off and then touch the case or something else that is grounded. I really think though as long as you stay away from any USB ports or any other ports it really shouldn't matter that much whether the computer is on or off in my opinion. If after you have done everything you can though to protect yourself against static electricity and you still have problems then you might need to look into other things such as a faulty power supply. I think though that it is just static electricity as that can do a number on things. Just keep an eye on things for about a month to be sure and then post back if you have other problems.
 
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Old 01-17-13, 01:49 PM
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That should do it for now. Thanks Man.
 
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