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  #46  
Old December 30th 18, 01:47 AM posted to microsoft.public.windowsxp.general
Buffalo[_3_]
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Default O.T. Cleaning computer

"J. P. Gilliver (John)" wrote in message
...

In message , Mr Pounder Esquire
writes:
J. P. Gilliver (John) wrote:
In message , Mr Pounder Esquire
writes:
[]
Oh, I've always earthed myself to a radiator before I take the
desktop into the garage.

Good idea, but voltage is relative - it's more important that you
touch (an exposed metal part of) the chassis before touching anything
inside - in theory, it probably doesn't matter if you're at 1 kV, if the
chassis is also at 1 kV. (Well, I exaggerate for effect, but YKWIM.) If
the
chassis and you are both grounded, even better. Often achievable by
leaving the mains lead (US: line cord) plugged in, assuming it's a
3-pin plug.


I need to take it into the garage and take the panels off before I can
touch
the chassis. Then I have to find an earth.

That might be one case where, indeed, you and the chassis are at the same
potential (thus you're unlikely to cause damage by a discharge), even if
that potential isn't earth potential. (Although I'm surprised you don't
have a handy earth in your garage - don't you have power there, e. g. for a
battery-charger? If so, I'd _hope_ it has earth terminals!)


JPG


Ever been frustrated that you can't *disagree* with a petition? If so,
visit 255soft.uk - and please pass it on, too.


If you leave the machine plugged in and just turn the switch on the PSU to
OFF, the machine will still be grounded through the 3 prong power plug. So,
just touch a metal part of the machine before touching any electronic part
and both will be at the same potential.
You don't need to find a different ground such as a radiator, etc.
Don't fret about blowing a can of compressed air on the heatsink, just do it
and get it over with.

--
Buffalo

Ads
  #47  
Old December 30th 18, 07:33 AM posted to microsoft.public.windowsxp.general
R.Wieser
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Posts: 1,302
Default O.T. Cleaning computer

Buffalo,

If you leave the machine plugged in and just turn the switch on the PSU to
OFF,


That might once have been be good advice, but not so much nowerdays.

These days computers can be "off" but still have parts of it powered so
that, for example, pressing a certain (or any) key on the (USB!) keyboard
will boot it.

Some motherboards have a LED to show its still (partially) powered even when
supposedly being off, but not all.

Pulling the powercord and waiting for a minute or so (to give the capacitors
in the power supply a chance to drain themselves) is the best way to go.
With, or without actual grounding.

So, just touch a metal part of the machine before touching any electronic
part and both will be at the same potential.


And that will be true even with power cable (and its grounding) removed. :-)

Regards,
Rudy Wieser


  #48  
Old December 31st 18, 06:28 PM posted to microsoft.public.windowsxp.general
Mark Twain
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Posts: 2,402
Default O.T. Cleaning computer

I always wear a grounding strap if I'm going to
be handling something inside the inside the computer.

As I stated earlier in the post this isn't just a
ground problem with the computer any longer; all the
outlets are open grounded which is why I have an
electrician coming on the 9th to replace and check all
the outlets.


Robert

  #49  
Old December 31st 18, 06:34 PM posted to microsoft.public.windowsxp.general
Mark Twain
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Posts: 2,402
Default O.T. Cleaning computer

The problem actually wasn't in the PSU but the APC
Surge Arrest which indicated a problem and when I
put a testor in the sockets it showed open ground.
All the sockets in the house except for one showed
open ground.

Robert
  #50  
Old December 31st 18, 07:40 PM posted to microsoft.public.windowsxp.general
Buffalo[_3_]
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Default O.T. Cleaning computer

"R.Wieser" wrote in message ...

Buffalo,

If you leave the machine plugged in and just turn the switch on the PSU
to OFF,


That might once have been be good advice, but not so much nowerdays.

These days computers can be "off" but still have parts of it powered so
that, for example, pressing a certain (or any) key on the (USB!) keyboard
will boot it.

Some motherboards have a LED to show its still (partially) powered even
when supposedly being off, but not all.

Pulling the powercord and waiting for a minute or so (to give the
capacitors in the power supply a chance to drain themselves) is the best
way to go. With, or without actual grounding.

So, just touch a metal part of the machine before touching any electronic
part and both will be at the same potential.


And that will be true even with power cable (and its grounding) removed.
:-)

Regards,
Rudy Wieser

Yes, I should have mentioned to make sure the outlet the PC was plugged into
was grounded properly.
I was talking about the switch on the PSU, not just turning the PC off. That
switch on the PSU should disconnect the hot and neutral wires but leave the
grounding wire connected. Perhaps some only disconnect the Hot wire.
Using a grounding strap is excellent and about the best way, but just
keeping one hand on a metal part of the PC and using the other hand to pick
up the part will usually be good enough without going crazy getting an earth
ground separate from the grounding in the outlet,
If you use a radiator or grounding electrode conductor, then make sure the
PC is not plugged in regardless if the switch on the PSU is OFF or not.
Different potentials can exist by doing that.
Overall, don't go crazy trying to find the best ground, etc. Use the
grounding strap method and/or use my suggestion.

--
Buffalo

  #51  
Old January 1st 19, 05:30 PM posted to microsoft.public.windowsxp.general
J. P. Gilliver (John)[_4_]
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Posts: 2,679
Default O.T. Cleaning computer

In message , R.Wieser
writes:
Buffalo,

If you leave the machine plugged in and just turn the switch on the PSU to
OFF,


That might once have been be good advice, but not so much nowerdays.


As he's reminded you in a later post, he did say "on the PSU". I've yet
to encounter a case where that isn't a real switch. (I have, however,
encountered PCs - I suppose I should really say PSUs - where there
_isn't_ a switch on the PSU itself.
[]
Pulling the powercord and waiting for a minute or so (to give the capacitors
in the power supply a chance to drain themselves) is the best way to go.
With, or without actual grounding.


It's a good way to ensure things are discharged, but it actually
_isolates_ the ground. Personally I've not found a case where such
isolation has caused a difference in potential anywhere near big enough
to cause harm, but ...

So, just touch a metal part of the machine before touching any electronic
part and both will be at the same potential.


And that will be true even with power cable (and its grounding) removed. :-)


.... I'd agree with the touch method. (Going the whole hog with a wrist
strap that has a clip for the chassis is even better, but I wouldn't buy
one just for the sake of it. YMMV.)

Regards,
Rudy Wieser


--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

"I'm a self-made man, thereby demonstrating once again the perils of unskilled
labor..." - Harlan Ellison
  #52  
Old January 1st 19, 06:52 PM posted to microsoft.public.windowsxp.general
R.Wieser
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Posts: 1,302
Default O.T. Cleaning computer

John,

As he's reminded you in a later post, he did say "on the PSU".


I've read it. I didn't want to make a point of it.

I have, however, encountered PCs - I suppose I should really say PSUs -
where there _isn't_ a switch on the PSU itself.


Same here. Just counted: from 9 'puters here three do *not* have such PSU
switches. Thats one out of each three.

But even for the ones that do have them I would not make any bets on them to
work as expected. If there is anything I've picked up when learning to be
an electrician is that assumptions like that will get you killed. Or, in
this case, might kill your motherboard. Pulling the plug and removing
it from the workingspace makes *certain* the power is off, and isn't any
more difficult than using that (rather tiny and sometimes awkwardy placed)
switch. Than again, may'be I'm just a bit over-cautious. :-)

Personally I've not found a case where such isolation has caused a
difference in potential anywhere near big enough to cause harm, but ...


I have. On certain (dry) days just a few steps over the (no doubt nylon)
carpet caused static discharges to occur when reaching for metal stuff like
doorknobs. Repeat 30 seconds later and the same would happen. Luckily I
didn't have to work on a puters innards there. :-)

The "touch the metal frame" was considered always a good thing to do, even
when wearing an earthing wristband. Largely because those tended to bleed
the excess charge off rather slowly (forgot how many megs the series
resistor exactly was), but also doing it automatically could save ones ass
when either forgetting to reconnect the earthing after grabbing a coffee or
simply when, on outside jobs, no earthing point or wristband was available.

Regards,
Rudy Wieser


  #53  
Old January 2nd 19, 02:00 AM posted to microsoft.public.windowsxp.general
J. P. Gilliver (John)[_4_]
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Posts: 2,679
Default O.T. Cleaning computer

In message , R.Wieser
writes:
John,

As he's reminded you in a later post, he did say "on the PSU".


I've read it. I didn't want to make a point of it.

I have, however, encountered PCs - I suppose I should really say PSUs -
where there _isn't_ a switch on the PSU itself.


Same here. Just counted: from 9 'puters here three do *not* have such PSU
switches. Thats one out of each three.

But even for the ones that do have them I would not make any bets on them to
work as expected. If there is anything I've picked up when learning to be
an electrician is that assumptions like that will get you killed. Or, in
this case, might kill your motherboard. Pulling the plug and removing
it from the workingspace makes *certain* the power is off, and isn't any


But does equally make *certain* that any earth connection it might have
contained is also broken. I would say "leave it plugged in but turn off
the power at the socket", but I'm aware that switched sockets, though
the norm in BS1363-land, are the exception elsewhere (EU, USA). [I'm
also under the impression that two-core - no earth - is commoner in the
USA, even where the connector at the PC end is the IEC320 that _does_
have an earth pin. I may be wrong there however.]

more difficult than using that (rather tiny and sometimes awkwardy placed)
switch. Than again, may'be I'm just a bit over-cautious. :-)


I think we're in agreement really.
[]
The "touch the metal frame" was considered always a good thing to do, even
when wearing an earthing wristband. Largely because those tended to bleed


I'd certainly do it. (Feeling better if knowing said chassis was also
earthed.)

the excess charge off rather slowly (forgot how many megs the series


1, usually, though only nominally (so ± 10% or even 20).

resistor exactly was), but also doing it automatically could save ones ass
when either forgetting to reconnect the earthing after grabbing a coffee or
simply when, on outside jobs, no earthing point or wristband was available.

Regards,
Rudy Wieser


--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Eve had an Apple, Adam had a Wang...
  #54  
Old January 2nd 19, 09:53 AM posted to microsoft.public.windowsxp.general
R.Wieser
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Posts: 1,302
Default O.T. Cleaning computer

John,

But does equally make *certain* that any earth connection it might have
contained is also broken


You seem to regard that earth connection as the holy grail. It isn't.

I would say "leave it plugged in but turn off the power at the socket"


You again assume that everything works as intended, possibly even (just not
in this case) betting your life on it, even though a simple, rather
effortless precaution would do away with such betting.

Even in this thread you could have read that Mark Twain mentioned that he
had a problem with *multiple* sockets not being earthed (because of a
failure somewhere). In the same way a dual- or single-wire socket switch
could fail - or be mis-wired! - leaving a hot wire to enter a device, just
not with a neutral out of it. Why take that chance ?

But granted, due to, in this case, the PSU working like an isolator (or
should be!) you would not even be aware of such failures.

I think we're in agreement really.


I think we are in regard to that the potential difference should be(come)
zero, just not on how to accomplish it. :-)

I'd certainly do it. (Feeling better if knowing said chassis was also
earthed.)


In that case use a *single* wire, posibly connected to the frame by way of
an alligator clip or alike.

Regards,
Rudy Wieser


  #55  
Old January 2nd 19, 10:15 PM posted to microsoft.public.windowsxp.general
Bill in Co[_3_]
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Posts: 303
Default O.T. Cleaning computer

R.Wieser wrote:
John,

But does equally make *certain* that any earth connection it might have
contained is also broken


You seem to regard that earth connection as the holy grail. It isn't.

I would say "leave it plugged in but turn off the power at the socket"


You again assume that everything works as intended, possibly even (just
not in this case) betting your life on it, even though a simple, rather
effortless precaution would do away with such betting.

Even in this thread you could have read that Mark Twain mentioned that he
had a problem with *multiple* sockets not being earthed (because of a
failure somewhere). In the same way a dual- or single-wire socket switch
could fail - or be mis-wired! - leaving a hot wire to enter a device, just
not with a neutral out of it. Why take that chance ?


Mark Twain? (I know this is unrelated, and my apologies for that, but I
thought Mark Twain died a century ago. So is the OP just assuming his name?
Seems weird).


  #56  
Old January 3rd 19, 02:20 AM posted to microsoft.public.windowsxp.general
J. P. Gilliver (John)[_4_]
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Posts: 2,679
Default O.T. Cleaning computer

In message , Bill in Co
writes:
R.Wieser wrote:
John,


Hi Rudi.

But does equally make *certain* that any earth connection it might have
contained is also broken


You seem to regard that earth connection as the holy grail. It isn't.


I don't. On the whole, I consider it preferable to have it, but having
the operator and the chassis at the _same_ potential is more important
from the point of minimising the chance of damage _to the equipment_.
Minimising the chance of damage (including death) to the _user_ probably
_is_ best served by yanking out _all_ connections, as you recommend.

I would say "leave it plugged in but turn off the power at the socket"

[]
Even in this thread you could have read that Mark Twain mentioned that he
had a problem with *multiple* sockets not being earthed (because of a
failure somewhere). In the same way a dual- or single-wire socket switch
could fail - or be mis-wired! - leaving a hot wire to enter a device, just
not with a neutral out of it. Why take that chance ?


In the UK, the socket switches are part of the socket. (I've never liked
them - mainly because I don't see the point of them - but I doubt they
_can_ be miswired [and still actually appear to work]. [An extension
_lead_, of course, which may be _feeding_ some switched sockets,
certainly _can_ be, of course.)

A mains lead (line cord) that _only_ has the earth/ground wire present -
i. e. cannot supply power - is arguably useful in some circumstances. (I
do not possess such.)

Mark Twain? (I know this is unrelated, and my apologies for that, but I
thought Mark Twain died a century ago. So is the OP just assuming his name?
Seems weird).

There's been a poster using that identity here for some time (years I
think). It could be his real name, though I _suspect_ not.

--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Personally, I don't like the Senate idea, I don't like the idea of having to
elect another bunch of overpaid incompetents. I don't like the idea of having
wholesale appointments by the PM of the day for domination of the second
chamber. I like anachronism. I like the idea of a bunch of unelected congenital
idiots getting in the way of a bunch of conmen. - Charles F. Hankel, 1998-3-19.
  #57  
Old January 3rd 19, 07:42 AM posted to microsoft.public.windowsxp.general
rp[_2_]
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Posts: 36
Default O.T. Cleaning computer

On Thu, 3 Jan 2019 01:20:15 +0000, J. P. Gilliver (John) wrote:

Mark Twain? (I know this is unrelated, and my apologies for that, but I
thought Mark Twain died a century ago. So is the OP just assuming his name?
Seems weird).

There's been a poster using that identity here for some time (years I
think). It could be his real name, though I _suspect_ not.


Well he signs his posts as Robert.

--
Regards - Rodney Pont
The from address exists but is mostly dumped,
please send any emails to the address below
e-mail rpont (at) gmail (dot) com


  #58  
Old January 3rd 19, 10:31 AM posted to microsoft.public.windowsxp.general
R.Wieser
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Posts: 1,302
Default O.T. Cleaning computer

John,

but I doubt they _can_ be miswired [and still actually appear to work]


As english sockets are constructed in such a way that the plug can only be
inserted in a single orientation and therefore most likely only switches the
(supposidly) "hot" wire, it would be easy: Just swap, when wiring the
socket, the neutral with the phase wire. And as (re-)connecting such
sockets can be done by the man of the house himself (or a bungling
electrician) ....

The circuit will still be open when "switched off" (no current can flow,
causing the attached device(s) to stop working), but the "hot" wire will
still enter the attached device. Worse, over what is assumed the neutral
wire ...

An extension _lead_, of course, which may be _feeding_ some switched
sockets, certainly _can_ be, of course.


Nope. Not when the single-orientation wiring is followed (which is
ofcourse subject to the same mistake as above).

Regards,
Rudy Wieser


  #59  
Old January 6th 19, 07:23 AM posted to microsoft.public.windowsxp.general
Mark Twain
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Posts: 2,402
Default O.T. Cleaning computer

I haven't been following this thread, but
since my name came up,.. here's the explanation.

I was using another common username when it
was suggested I change it to something more
unique so it would be more easily recognizable.

I'm a history buff and just choose Mark Twain
that's really all there is to it.

Robert



  #60  
Old January 6th 19, 07:28 AM posted to microsoft.public.windowsxp.general
Mark Twain
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Posts: 2,402
Default O.T. Cleaning computer

Yes Mark Twain died a century ago but
Why does it seem weird? It's just a
username. I could of put anything and
just decided to use that.

Robert
 




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