We’re going to install more RAM in this computer, and while reading about it on the Web, I immediately bumped up against the instructions to equip myself with an anti-static wrist strap. Do I have to make another trip down to Office Max and pay seven bucks for one, or is there a way to make one from common household materials?
Depends on how safe you want to be. Grounding straps have a resistor, typically one megohm I believe, built into the strap to keep you from frying should you touch a hot wire. If you have such a resistor lying around, you could probably make yourself a functional equivalent to a commercial strap. Or, you could throw caution to the wind, and leave the resistor out.
I usually just keep a hand or an elbow on the grounded case when I’m working. This method has all the danger of a resistorless strap without all the convenience.
Well, is the purpose of it to actually keep yourself from being fried, or is the purpose of it to keep static from discharging and frying your computer? Or both? Or what?
Safety is important to me, but if it’s just to discharge static before it hits the computer’s innards, it seems like I could cobble something together from paper clips and duct tape, save a few bucks and a trip to Office Max, which this being the day after Thanksgiving, was a ZOO. I was already there once this morning to get the RAM.
The purpose is to prevent a discharge of static electricity from damaging computer innards. If your computer has a grounded (three-prong) plug, you’re most likely OK if you leave it plugged into the wall socket (but definitely with the power OFF) and touch the grounded case before monkeying with the RAM. That’s what Mandarax describes in his/her last paragraph.
You could also spray Static Guard (normally used for clothing) all around the place before you open up the computer.
Er, I’m not supposed to unplug the computer to do this? I thought it was like monkeying around with the VCR, that you always unplug it first. 
Re: Un-plugging or not.
In the bad old days, when men were real men, and small furry creatures from Andromeda Centauri were real small furry creatures from Andromeda Centaury, a power supply was a real power supply. Nowadays Power Supplies do all sorts of nastinesses, even when ‘switched off’.
In short:
The idea behind leaving the computer plugged in comes from the assumption that the chassis will still be connected to ground, and everything else is switched off if you switch it off.
Unfortunatelly the second assumption is false. Modern computers supply power to the PCI even when ‘switched off’.
Thus, the best to do is to unplug the computer, connect the chassis to ground (if possible via a largish resistor, but by no means necessary), and then connect yourself to the chassis.
The first step is easily done with some copper wire, and the second step can be achieved with your left hand.
Bummer, botched the hitchhikers reference… The small furry creatures mentioned were indeed more likely to have come from Alpha Centauri.
Go to radioshack. Get one for 2 bux. Sure best buy and circuit city and etc are busy today, but I doubt radioshack is. Besides, there’s one on every corner.
Dont fry the memory!
If you are not in a particularly staticy environment, just touching the metal case should be enough. Most people don’t use ground straps.
Touch the kitchen faucet. It’s grounded. 
If you wish to make yourself a pretty darn good anti-static grounding wrist strap, cannibalize a power cord – the kind that has the three-pronged plug going into the wall on one end and the “appliance” three-socketed plug that plugs into the back of a CPU, monitor, external device, etc.
Using heavy-duty wire cutters, remove all prongs except for the ground prong. Cut a piece of cardboard out of such as a shoebox or cereal box in the shape of the plug surface with a hole for the ground prong to push through as added barrier to any live current going up-wire. Chop through the insulation on the cord somewhere in the middle and expose a length of the ground strand. Take a length of fabric (an old bathrobe tie cord works well) and snip a little cut into it, feed some ground strand into the cut, then sew it closed behind the ground strand, in such a way that a narrow strip of exposed ground wire lays across the surface of the fabric on one side.
Plug the modified three-prong plug with the cardboard insulator into the wall (only the ground plug will contact anything), plug the other end into the appliance-cord receptable on the back of the CPU, and tie the bathrobe cord around your wrist.
I think that last one is right up there with sticking your finger in a light socket.
I had either a dead MB or uprocessor. I turned off the PC, left it plugged in a switched micro ps. This would tell me if the MB or the up was dead. Anyway, as I dropped the chip into the zero force insertion socker, the damn thing booted…
Now I had two dead ups and MBs.
That’s an extremely bad ground strap Ahunter3. Aside from the rather dodgy mechanical construction, it’s also an extremely low impedence path to ground which means that any built up charge is going to discharge very very quickly. True ground straps have a high impedence (typically 1 meg) so that any charge dissipates slowly and more safely.
Go to Radio Shack (as much as I hate to reccomend them for anything), buy the el-cheapo ground strap, clip it on to the case (which should be unplugged) and then get to work.
Try to handle all boards (even memory dimms) by the edges and don’t touch the electrical contacts.
Ringo, be very careful what you spray near a computer. I don’t know how safe clothing static guard spray is for electronics, but in general all kinds of things can get sucked into disk drives and the power supply where they generally don’t do much good.
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Do not ever suggest leaving an appliance plugged in when working on it, esp. with the case off. This is a Bad Bad idea. Leave the dangerous stuff to the pros. Everyday folk should always unplug.
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It is not necessary that you be grounded. In fact, it is only nec. that you and what you are working on be at the same potential. Ergo, touch a bare part of the case.
Okay, so to top off a thread full of confusing and contradictory advice, now FTG the acknowledged “Safety First” nut (and I mean that in a nice way, FTG) is telling me–unsurprisingly–that I must unplug the computer, but surprisingly, that I do not need to buy a wrist static strap at Radio Shack.
Now I am more confused than ever and am beginning to regret having asked the question. Can we get some kind of consensus here, people?
Vote. Computer is currently plugged into power strip.
- Unplug computer from power strip, yes or no.
- Unplug power strip from wall, yes or no.
- Use Radio Shack wrist strap, yes or no.
- Just touch metal case, yes or no.
- Build AHunter’s thingamajig, yes or no.
Is AHunter joking or not, about the do-it-yourself strap? I have NO way of telling.
1-y
2-y
3-eh. It couldn’t hurt.
4-y
5-n
Do either 1 or 2, it doesn’t matter much which. I usually just unplug the power cord from the back of the case, because it’s usually the easiest to get to, and you know for sure you’re disconnected.
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Can’t hurt, but I don’t usually bother for such a simple operation, and I even have one of the official wrist straps in my toolkit.
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Yes.
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No. It would probably work. But it might not, depending on how a given outlet is wired, and if you had a badly mis-wired or defective outlet, you could give yourself a hell of shock. The chances of this are extremely slim, but why take a chance?
For a simple memory upgrade, my procedure is this:
Get the case unplugged, open and ready so that you can reach the memory slots.
Put the new memory stick (while still in its protective sleeve) on a bare metal part of the case.
Touch a bare metal part of the case for a 5 count.
(If needed) Pull out the old memory stick.
Open the new memory stick and put it in place.
Get the covers back on, everything plugged back in, and fire it up.
A last note on the “unplug or not” issue. In reality, even if you leave the box plugged in, the chances of getting anything stronger than a mild tingle from your average PC are pretty slim, unless you crack open the power supply.
But that’s your average PC. It’s the non-average stuff that kills you. I routinely work on boxes that are plugged in. But I know what the components are, I know what I can touch and what I can’t, and I know how to recognize something that is not standard. And while I acknowledge that I take a small risk doing this, it’s an informed risk, taken with (what I consider to be) appropriate precautions.
So the moral is: If you don’t know this stuff, don’t take the chance! Play it safe all the way. If you’re in doubt, take it someone else. $50 isn’t worth it.
So unplug it, touch the case, be a little careful with the components, and you’ll be fine.
Good luck.
Ugly
Well, first of all let me say that I have a degree in electrical engineering, plus formal training about ESD on the job. If that doesn’t qualify as an expert then I don’t know what does.
You need to unplug the computer from the AC source, so do either 1 or 2, or both, but not neither.
As for 3 and 4, if you do 3 then you’re safe. Attach the ground strap to the metal portion of the case. Technically you can get away with doing just 4, but that puts all of the responsibility on you to make sure that you keep touching the case or the power supply housing periodically if you move your feet around, etc. Personally, I almost never bother with a ground strap, but then I am very concious about what I touch and when. The regulations for people who do this sort of thing for a living are to always use a ground strap, because you can’t be certain that someone won’t good otherwise.
- No way in hell. Not only will it help get you electrocuted if you accidentally touch something hot, but it will also provide a low impedence path to ground for any built up charge which could cause a dangerously high current to result (dangerously high for the parts you are trying to protect from ESD, I mean). If you at least put a 1 meg resistor in series with his god-awful gadget then it wouldn’t be so bad. Still, it’s not a very mechanically sound ground strap. You’re better off going with the el cheapo Radio Shack version.