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Posted 17 October 2015 - 10:34 PM
Posted 18 October 2015 - 05:37 PM
Your question is a very fair one but the answer isn't easy !
The risk is that some electronic components are vulnerable to static electricity, of that there is no doubt. Probably the most vulnerable are RAM chips. However the real problem is the possibly significantly different voltages present on your body and on the equipment you are working on, and it is this difference that is the important part.
As you say, on a desktop you can touch some bare metal part of the chassis and equalise any voltage difference. On a laptop the problem doesn't really arise until you get the case partly stripped to get to the mobo. I would suggest that at this point you touch say the heat pipe from the CPU as this is screwed to the mobo and these screws normally contact the mobo at the earth plain. Even if you are only opening the hatch on the back to change RAM chips the clips that locate them are normally earthed and this should equalise voltages.
I wouldn't use the power lead for your laptop charger as you suggest. Nearly all such cords have 0V on the outside - bare metal connector - but I believe there are one or two where this is live, ie about +20V. Not a good idea. Connecting your strap to the case of your guitar amp would be a much better idea as this is almost certainly earthed.
What not to do is what I did once upon a time, until the folly of my ways was pointed out to me. I think it is still lurking somewhere in the depths of my electrical toolbox. Take a standard power plug and a single strand of insulated wire. Connect this to the earth terminal. Strip eight or nine inches of insulation off the other end and fasten around wrist. Earthed.
Unless for some reason the wire becomes dislodged and contacts the live terminal. We use 220/240V AC in the UK - this is not good for your health ! In the Americas I understand the standard voltage is 110V AC, This will still give you a nasty belt and make your hair curl.
Having said all that, the risk is not as great as some would have you believe. I trained as an electronics tech back in about 1980 and have been playing with computers since the early 90's and I don't think I have wrecked anything due to static electricity yet.
Posted 21 October 2015 - 11:45 PM
Thanks for the responses. I really appreciate it.
I've never used the strap myself and I've repaired PCs for approximately 15 years. However, my experience with laptops is minimal and even before when I did repair a few laptops, I always had desktops around to periodically touch. The problem is, I moved across country and so I had to give up my whole dinosaur graveyard...no more desktops. Now, my new setup is not very friendly to puter repair work, as there's a super fluffy carpet, my desk is all wood. The only thing close by that has metal is my electrical guitar and amp. So, I went with grabbing the metal bits on my guitar a few times as I worked. I fixed my laptop and still have yet to use the strap. LOL!
Again, thanks for the responses. I'm sure there are others that may have the same question, so it's good to have it here as a reference. :D
Posted 22 October 2015 - 12:04 AM
Heh, well in that case um.. Don't wear a sweater, probably best to have bare feet, and what you can touch is the screws that hold light switch and outlet plates on because they are grounded.
Posted 22 October 2015 - 12:12 AM
As I learned from working with electricians, you can't always trust that outlets and switches are grounded. Unless you know for sure, it's questionable. There are testers out there, but I don't take it the average joe would have one sitting around...
Posted 22 October 2015 - 12:55 PM
My work area has a grounded bench and all the outlets are up to current code. Grounding may not be needed on desktops where most everything is surrounded by chassis. Laptops still need grounding to insure you don't induce a static failure. You could ground to desktop, if just to dissipate any built up charges.
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