On Sat, 25 Sep 2004 23:37:13 +0100, Richard Urwin
<[EMAIL PROTECTED]> wrote:
> On Saturday 25 Sep 2004 4:55 pm, Erylon Hines wrote:
> > On Saturday 25 September 2004 07:33 am, Lyvim Xaphir wrote:
> > | But for all the *newbies* here reading this, statically wounded
> > | circuits can show weird symptoms months after installation.
> > | Sometimes weird stuff like what Ron is seeing.  That includes
> > | (especially) motherboards.  It's best to have a grounded static
> > | wrist band on when you are inside your computer and before you
> > | remove the static packaging from any new component.  (static
> > | packaging isn't there because it's pretty.)  If you always do this,
> > | you can be sure that you've kept your equipment in mint condition.
> > |
> > | LX
> >
> > A note on grounding.  Most times when I see instructions for this it
> > says something like, "Unplug your computer".
> >
> > DO NOT UNPLUG YOUR COMPUTER.  If you do, you will remove the machine
> > from the system ground and your box will be "floating".  Any time
> > equipment is floating, there is a chance that it's potential will be
> > different from ground potential.  Turn it off, but leave it plugged
> > in and the case will be bonded. If you are not on a workbench with a
> > known good bond to ground, attach yourself to the metal part of the
> > case, and you are good to go.
> 
> I think "Which" was told off and had to publish a retraction not so long
> ago for publicly giving that bit of advice.
> 
> Some things to bear in mind:
> 1. If there's an earth fault the live wire is connected to you.
> 2. The switch is in the live wire. If, like I did, you have an extension
> cable with the live and neutral swapped, then the live parts are still
> live. It may still be a problem with a properly wired connection if
> your neutral is at a different potential to your earth. OK, not such a
> problem with a PC because the PSU is enclosed.
> 3. Anti-static straps have 1MegOhm resistors in them. Without such they
> are considered serious health and safety violations. Since every piece
> of anti-static equipment has that, the actual resistance to earth of
> professional gear is usually several meg ohms.
> 
> Personally, If I have my wrist strap with me I leave the box plugged in
> and use it. If I don't then I still leave it plugged in, but just touch
> the case frequently to keep myself at the same potential. I think very
> long and hard before I decide to connect myself to the case with a
> piece of wire.
> 
> Another word of warning: some PSUs do not have an off switch. The button
> on the front of an ATX case leaves power to some parts of the
> motherboard. If there isn't a rocker switch on the PSU, you can not
> leave it plugged in without having an external switch somewhere.

The best external switch, for boxes without an external (rear) switch,
is using a good quality powerbar that has a switch - not just a
fuse....

yikes.... cross wiring is one thing, but stay away from carpets
altogether.  Of all things to happen a number of years ago (1994 or 95
I think) was I killed a keyboard as I stepped away from my grounded
box, walked across the carpeted room, picked up the keyboard (zap) and
I couldn't get the box to boot.  Puzzled for several days, I had to
bring it in to a shop, twice for them to tell me the box was perfect. 
Lo and behold I wasn't bringing in the peripherals.   I stuck in a
floppy and OS2-warp disk, powered up, only for the install program to
tell me I had keyboard errors - buffer overflow.

I didn't even know I zapped the KB but walking about 16 feet on
hair-raising carpet must have overloaded it, and yet I was so careful
with installing the new drive.

Regards,
Sean Pritchard

-- 
Registered Linux User# 156507
Mandrake User Since May 1999

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