Unplugging power cord

[David Maynard]

Plug the PC power cord into a "power strip" that is plugged into the
electrical outlet. The "power strip" is turned OFF. Your PC is grounded,
but it receives no current. Any suggestion that you remove the power cord
is, of course, ridiculous, since there is no grounding path.

No, it isn't 'ridiculous' because there is no great over-riding cosmic
significance to having the 'earth ground' connection. What matters is
everything being at the same potential, whether it's 'earth ground' or not.

 

[CBFalconer]

Ah, thank you. I was assuming that discharging static from your
body to a case with the mains lead out could raise the potential
of the case to a level sufficient to damage electronic components.

Bushwah. Static charges can accumulate. Find a Windhurst machine
to see what can be done. That is a baby version of a Van de Graaf
generator, which can often generate 5 megavolts. Wattage is
another matter. The Windhurst can easily generate 3 to 5 inch
sparks.

The saving grace is that modern circuits tend to have protective
diodes to bypass the sensitive gates.

 

[Chris Stolworthy]

I see in the manual for my new motherboard - an MSI K8N Neo - it says to
remove the power cord when inserting and removing cards and DIMMs.

Is this good advice or excessive caution? With my current board I never did
that.

I would list it under excessive caution. I have never unplugged a PC when
installing RAM just shut it down.

 

[CBFalconer]

.... snip ...

Yes. Well, that has the same effect, except for the times I've
seen people accidentally turn it back on.

Dern rare to accidentally plug the power cord back in, though.

Helpful 6 year old: I see why it doesn't work Daddy <plug>

 

[David Maynard]

David Maynard wrote:

... snip ...



Helpful 6 year old: I see why it doesn't work Daddy <plug>

LOL

Not really an 'accident' then, is it? hehe

Reminds me of a Sylvester the Cat, and his son, cartoon. Kid ends up
shooting him and setting his tail on fire while 'saving' him and Sylvester,
snuffing out the tail flame, comments "let's just not help 'save' dear old
dad any more, hmmm?"

 

[kony]

I see in the manual for my new motherboard - an MSI K8N Neo - it says to
remove the power cord when inserting and removing cards and DIMMs.

Is this good advice or excessive caution? With my current board I never did
that.

Many boards have an LED on them to warn you when it's still
powered by 5VSB... wonder why they'd do that...

 

[Parish]

Many boards have an LED on them to warn you when it's still
powered by 5VSB... wonder why they'd do that...

So you can see the slots if your PC is under the desk, like mine

Parish

 

[Derek Baker]

Duh! Must get some new glasses - I read your original post as *eight*
pounds, hence my keeness to know whether it was new

Parish

That's funny: I typed eight first, but corrected it before I posted.

 

[jim.]

Bushwah. Static charges can accumulate. Find a Windhurst machine
to see what can be done. That is a baby version of a Van de Graaf
generator, which can often generate 5 megavolts. Wattage is
another matter. The Windhurst can easily generate 3 to 5 inch
sparks.

Yes I think we've all played with them, but your likening a case to a leyden
jar doesn't hold much water ;-)

 

[Bob]

No, it isn't 'ridiculous' because there is no great over-riding cosmic
significance to having the 'earth ground' connection. What matters is
everything being at the same potential, whether it's 'earth ground' or not.

Except that there is no guarantee that everything is at the same potential.
That is why you ground the PC and wear a grounding strap. Done deal.

 

[jim.]

No, it isn't 'ridiculous' because there is no great over-riding cosmic
significance to having the 'earth ground' connection. What matters is
everything being at the same potential, whether it's 'earth ground' or

not.

Dead right.
This one crops up with monotonous regularity and a significant group seem
unable to get their heads round it (every time).
Try explaining how the anti-static bag saves cmos devices without being
earthed throughout its postal perambulations, that might work.
but I doubt it ;-)

 

[Rob Morley]

Except that there is no guarantee that everything is at the same potential.

There is if you touch everything to the chassis.

That is why you ground the PC and wear a grounding strap. Done deal.

The strap equalises potential, it will do that whether the chassis is
grounded or not.

 

[kony]

There is if you touch everything to the chassis.

.... and that's the main thing we shouldn't do, cause equalized
potential by having the held component be the traveled path of
charge to the case. Ground strap is good, but unnecessary...
main thing is to have parts alreay next to system, touch
case/ground before handling parts. If environment is so prone to
static that this isn't sufficient then best course is altering
environment.

 

[DaveW]

The P4 based motherboards have power on ALL THE TIME to the motherboard,
even when the front power switch is Off.

 

[Michael Salem]

... and that's the main thing we shouldn't do, cause equalized
potential by having the held component be the traveled path of
charge to the case.

?

 

[Bob]

... and that's the main thing we shouldn't do, cause equalized
potential by having the held component be the traveled path of
charge to the case. Ground strap is good, but unnecessary...
main thing is to have parts alreay next to system, touch
case/ground before handling parts. If environment is so prone to
static that this isn't sufficient then best course is altering
environment.

Er, how do you alter the environment? Obviously, I do not expect a reply.

 

[kony]

Er, how do you alter the environment? Obviously, I do not expect a reply.

Then why ask the question?

Altering the environment means doing things not dependent on
installer action to reduce risk. For example, grounded
workstation or desk, increasing air humidity, ionizing air,
anti-static treament for carpeting. Further, setting up storage
area for parts adjacent to the construction so travel to and fro
is minimized.

 

[kony]

?

What's the mystery?

Touching something to the chassis to equalize potential is
causing flow across that object being touched to chassis. I
took "component" to mean the part, not the installer's hand prior
to handling that part.

 

[Michael Salem]

What's the mystery?

Parsing that sentence

 

[David Maynard]

Except that there is no guarantee that everything is at the same potential.

Yes there is: touch the case.

That is why you ground the PC and wear a grounding strap. Done deal.

I didn't say that wouldn't work. What I said was it isn't the only way.