Installing MoBo

Motherboard and chassis grounds should not be electrically
connected at multiple points. Concept is called single point
grounding - also used to make A/D converters work reliable and
to eliminate hum among stereo components. An experiment
easily demonstrates the problem if you can make 'painful'
static electricity.

Put the computer on a glass table top (because even wood is
an electrical conductor). While computer is running, static
discharge your body to various corners of a computer chassis.
Computer should work just fine and uninterrupted. However, if
the motherboard ground has too many electrical connections to
chassis, then computer will crash.

The one electrically conductive standoff 'motherboard to
chassis' should be in same area as power connector and IO
boards. When normal static electric discharges occur, then
two electrically conductive paths from chassis to motherboard
ground do not conduct that static discharge via motherboard
ground plane.

Nylon standoffs are the simple solution. Motherboard's
green solder mask is not intended to be an electrical
insulator (even though some assume so). Nylon shoulder
washers keep metallic standoffs from penetrating the solder
mask; from making motherboard ground contact. But simpler is
to obtain 'snap in' nylon standoffs to eliminate accidental
shorts to motherboard AND to make computer resistant to static
electric induced crashes.

wrote:
Thank you guys.
you were a big help.
schreef in bericht
...

w_tom wrote:

Motherboard and chassis grounds should not be electrically
connected at multiple points. Concept is called single point
grounding - also used to make A/D converters work reliable and
to eliminate hum among stereo components. An experiment
easily demonstrates the problem if you can make 'painful'
static electricity.

The term "single point grounding" is buzzword nonsense in this
context. The reader can do a Usenet archive search for "single point
grounding" and then scroll down the page, noticing most of the posts
were made by "w_tom".

Antec cases come with no washers, but they come with electrically
conducting brass mainboards standoffs. Microstar International and
Asus mainboards have electricity conductive solder coated rings
around their mounting holes which are directly connected to device
ground pins, and they do not come with washers either.

You don't have to be a rocket scientist to figure out what that
means.

If what you are saying were true, which it isn't, given the contrary
circumstances, motherboard/mainboard makers would advise us to use
insulation. Clearly, we are expected to ground the mainboard at
those points. (I am speaking about mainboards which have electricity
conductive rings around their mounting holes.)

Nylon standoffs are the simple solution.

They would be, if what you're saying were true. Nylon standoffs
would be cheaper than electricity conducting brass standoffs also.

Motherboard's green solder mask is not intended to be an
electrical insulator (even though some assume so).

Electricity conductive mounting hole rings are not intended to be
electrical insulators either. The idea that any manufacturer would
use electricity conductive material for an insulator is bizarre in
my opinion.








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In the junior high school lunch room, where basic knowledge
is minimal, the child learns how insults can replace fact.
However adults learn facts before posting. If John Doe had
basic electrical knowledge, then he would have discovered
numerous references to single point grounding. Instead, John
Doe searched newsgroups (not the web) for electrical
principals he never bothered to learn.

A John Doe educated in simple electrical concepts would have
found numerous engineering discussions about single point
ground. One from Microchip - a microprocessor manufacturer:
http://www.microchipc.com/PIC_tips_3.asp
The best way to handle the ground problem is to have different
ground systems that connect at only one point. The precision
analog REFERENCE ground should always be designed so that an
absolute minimum of current actually flows through it. In
practice this is accomplished by having all reference ground
connections terminating at a SINGLE POINT.

This is but one example. Literally every electronic part
manufacturer provides application notes that teach variations
of the single point grounding. Again, in stereo and PA
systems, the same concept eliminates something called ground
loops.

I don't know who John Doe is. But quickly he does what kids
in a lunch room do. Kids don't know facts, so instead, they
attack the messenger. John Doe obviously does not possess
basic electrical knowledge. He demonstrates why so many
computer assemblers are 'experts' - needs no freaking
education.

Don't be mislead by the naive. Make a computer systems more
reliable. A connection between motherboard logic ground and
chassis ground should be single point. With dry weather
approaching, the previously posted static electricity
experiment can demonstrate the principles. Notice the
difference between this poster and John Doe. This poster
cites professional sources AND provides experiments (static
shock a computer, or stereo system ground loops) to
demonstrate the electrical concept.

That keyboard beneath your fingers uses same single point
ground concepts. Pin 3 or pin 4 is the DC ground. Connector
shell and shield inside wire connects to DC ground at a single
point. Why? Some keyboards go even farther to keep shield
ground separate from DC ground until both meet, instead, at
motherboard. Just another example of single point grounds to
avoid failures from static electricity and noise. Two
separate grounds that meet at a common point.

Single point ground justified by electrical reasons - when
one first learns these basic electrical principles. This post
includes design examples AND the principles behind that
design. Principles that apparently so confused John Doe that
he searches newsgroups for a technical explanation rather than
consult engineering books or engineering application notes.

Best to mount a motherboard to chassis with only one
connection between the two grounds. Eliminate noise between
ground pins of computer's Integrated Circuits to make computer
more reliable. No ground transients through motherboard logic
ground means a stable computer system. Motherboard logic
ground best joins chassis ground at a single point using a
single conductive standoff.

John Doe wrote:
The term "single point grounding" is buzzword nonsense in this
context. The reader can do a Usenet archive search for "single point
grounding" and then scroll down the page, noticing most of the posts
were made by "w_tom".

Antec cases come with no washers, but they come with electrically
conducting brass mainboards standoffs. Microstar International and
Asus mainboards have electricity conductive solder coated rings
around their mounting holes which are directly connected to device
ground pins, and they do not come with washers either.

You don't have to be a rocket scientist to figure out what that
means.

If what you are saying were true, which it isn't, given the contrary
circumstances, motherboard/mainboard makers would advise us to use
insulation. Clearly, we are expected to ground the mainboard at
those points. (I am speaking about mainboards which have electricity
conductive rings around their mounting holes.)

Nylon standoffs are the simple solution.

They would be, if what you're saying were true. Nylon standoffs
would be cheaper than electricity conducting brass standoffs also.

Motherboard's green solder mask is not intended to be an
electrical insulator (even though some assume so).

Electricity conductive mounting hole rings are not intended to be
electrical insulators either. The idea that any manufacturer would
use electricity conductive material for an insulator is bizarre in
my opinion.

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w_tom wrote:

A John Doe educated in simple electrical concepts would have
found numerous engineering discussions about single point
ground. One from Microchip - a microprocessor manufacturer:
http://www.microchipc.com/PIC_tips_3.asp

Liar.

"[That] site is a completely separate site to www.microchip.com, and
is maintained independently of Microchip Ltd., manufacturers of the
PIC micro."

Literally every electronic part manufacturer provides application
notes that teach variations of the single point grounding.

In what appears to be a play with semantics, one then has to
ask where that one point is and how do we get there.

I don't know who John Doe is. But quickly he does what kids
in a lunch room do. Kids don't know facts, so instead, they
attack the messenger.

I was looking for the message. I found the message carried mainly by
one w_tom.

John Doe obviously does not possess basic electrical knowledge.

Troll.

I'm not an engineer, I learned most of what I know about electronics
from National Semiconductor's many data books. However, from that I
have designed and built digital clocks, a simple frequency counter,
light and touch sensing switches, etc. One of my designs was
published in electronics' magazines, enhanced by a professor at
Rochester University for use in his lectures (he gave me credit,
that's how I found out), and his made into a product by 3M.

He demonstrates why so many computer assemblers are 'experts' -
needs no freaking education.

Hello there w_tom.

Don't be mislead by the naive.

Troll.

Make a computer systems more reliable. A connection between
motherboard logic ground and chassis ground should be single point.

I think maybe w_tom is trying to diverge at this point to talk about
logic versus analog ground. I have read about that, however it has
nothing to do with this.

With dry weather approaching, the previously posted static
electricity experiment can demonstrate the principles.

What w_tom is referring to is the idea that static electricity
discharge from you to the case could hurt your mainboard/motherboard
if it is connected through main board standoffs. The capacitance of
a computer case would likely absorb any static electricity you can
generate. The reverse is more likely true and beneficial. Unwanted
electricity generated on the main board would more easily find a way
to the case.

Again, to be clear, I'm talking about mainboards which include
electricity conductive rings around the mounting holes. What the
maker chooses to connect those points to, whether digital or analog
device ground, is up to the maker. But obviously those points are
meant to be connected to the case.

Notice the difference between this poster and John Doe. This
poster cites professional sources AND provides experiments (static
shock a computer, or stereo system ground loops) to
demonstrate the electrical concept.

This poster? You?

... Principles that apparently so confused John Doe that
he searches newsgroups for a technical explanation

Usenet is great for semantics. For example if someone comes along
and uses an impressive sounding, but pretty much nonsensical term,
you can usually tell by doing a search in the Usenet archives
(Google).

rather than consult engineering books or engineering application
notes.

I don't do research to support someone else's silly sounding
claim.

I would be impressed and surprised if any mainboard/motherboard
manufacturer or computer case manufacturer supported your argument.
Without that, the circumstances rule.

snipped more trolling






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w_tom wrote:

In the junior high school lunch room, where basic knowledge
is minimal, the child learns how insults can replace fact.
However adults learn facts before posting. If John Doe had
basic electrical knowledge, then he would have discovered
numerous references to single point grounding. Instead, John
Doe searched newsgroups (not the web) for electrical
principals he never bothered to learn.

A John Doe educated in simple electrical concepts would have
found numerous engineering discussions about single point
ground. One from Microchip - a microprocessor manufacturer:
http://www.microchipc.com/PIC_tips_3.asp

That's a typical analog single point circuit ground, the primary purpose
being to isolate the analog section from the digital section's switching
induced ground noise; which has nothing to do with chassis/motherboard
shield grounding.

It is intuitively obvious to even the most casual observer, however, that a
9.6 inch by 9.6 inch ground planed mATX motherboard does not present a
'single point ground' to it's components. The point being, while a 'single
point ground' has specific uses, to then go dancing around claiming it's
'the solution' to everything under the sun is to not understand it.


The best way to handle the ground problem is to have different
ground systems that connect at only one point. The precision
analog REFERENCE ground should always be designed so that an
absolute minimum of current actually flows through it. In
practice this is accomplished by having all reference ground
connections terminating at a SINGLE POINT.


This is but one example. Literally every electronic part
manufacturer provides application notes that teach variations
of the single point grounding. Again, in stereo and PA
systems, the same concept eliminates something called ground
loops.

Yes, single point ground techniques are well known. It is also well known
that single point grounding is only effective with 1 Mhz signals (in
general) and, in case anyone failed to notice, PC's passed that mark with
the very first one (not to mention that switching transients generate much
higher frequencies than the 'clock' rates).

'Single point ground' becomes useless at high frequencies because, while
the potential is '0' at the 'single point ground', the induced field is a
maximum 1/4 (and every odd quarter) wavelength from the 'single point
ground'; not that it need be 'maximum' to be a problem. If you can't get it
done in well under 1/20 wavelength then you need another solution.


I don't know who John Doe is. But quickly he does what kids
in a lunch room do. Kids don't know facts, so instead, they
attack the messenger.

You certainly out did him on that score.

John Doe obviously does not possess
basic electrical knowledge. He demonstrates why so many
computer assemblers are 'experts' - needs no freaking
education.

Don't be mislead by the naive. Make a computer systems more
reliable. A connection between motherboard logic ground and
chassis ground should be single point. With dry weather
approaching, the previously posted static electricity
experiment can demonstrate the principles. Notice the
difference between this poster and John Doe. This poster
cites professional sources AND provides experiments (static
shock a computer, or stereo system ground loops) to
demonstrate the electrical concept.

That keyboard beneath your fingers uses same single point
ground concepts. Pin 3 or pin 4 is the DC ground. Connector
shell and shield inside wire connects to DC ground at a single
point. Why? Some keyboards go even farther to keep shield
ground separate from DC ground until both meet, instead, at
motherboard. Just another example of single point grounds to
avoid failures from static electricity and noise. Two
separate grounds that meet at a common point.

Single point ground justified by electrical reasons - when
one first learns these basic electrical principles. This post
includes design examples AND the principles behind that
design. Principles that apparently so confused John Doe that
he searches newsgroups for a technical explanation rather than
consult engineering books or engineering application notes.

For someone who pontificates so much about learning electrical principles
you sure jumble them up all over the place, scrambling analog, digital, low
frequency, high frequency, power, cable interconnect, circuit ground,
chassis ground, protective ground, and EMI shielding into a hodge podge of
misapplication.


Best to mount a motherboard to chassis with only one
connection between the two grounds. Eliminate noise between
ground pins of computer's Integrated Circuits to make computer
more reliable. No ground transients through motherboard logic
ground means a stable computer system. Motherboard logic
ground best joins chassis ground at a single point using a
single conductive standoff.

John Doe's observation of metal standoffs and a motherboard manufacturer
controlling whether or not their mounting holes are intentionally connected
to the board's ground plane, or not, is spot on and makes the point moot.

If a 'single point ground' is desirable then the manufacturer will make a
'single point' the ground connection, or provide installation instructions
on what the assembler should do to ensure it.


John Doe wrote:

The term "single point grounding" is buzzword nonsense in this
context. The reader can do a Usenet archive search for "single point
grounding" and then scroll down the page, noticing most of the posts
were made by "w_tom".

Antec cases come with no washers, but they come with electrically
conducting brass mainboards standoffs. Microstar International and
Asus mainboards have electricity conductive solder coated rings
around their mounting holes which are directly connected to device
ground pins, and they do not come with washers either.

You don't have to be a rocket scientist to figure out what that
means.

If what you are saying were true, which it isn't, given the contrary
circumstances, motherboard/mainboard makers would advise us to use
insulation. Clearly, we are expected to ground the mainboard at
those points. (I am speaking about mainboards which have electricity
conductive rings around their mounting holes.)


Nylon standoffs are the simple solution.

They would be, if what you're saying were true. Nylon standoffs
would be cheaper than electricity conducting brass standoffs also.


Motherboard's green solder mask is not intended to be an
electrical insulator (even though some assume so).

Electricity conductive mounting hole rings are not intended to be
electrical insulators either. The idea that any manufacturer would
use electricity conductive material for an insulator is bizarre in
my opinion.

"John Doe" wrote in message
...
w_tom wrote:

Motherboard and chassis grounds should not be electrically
connected at multiple points. Concept is called single point
grounding - also used to make A/D converters work reliable and
to eliminate hum among stereo components. An experiment
easily demonstrates the problem if you can make 'painful'
static electricity.

The term "single point grounding" is buzzword nonsense in this
context. The reader can do a Usenet archive search for "single point
grounding" and then scroll down the page, noticing most of the posts
were made by "w_tom".

Antec cases come with no washers, but they come with electrically
conducting brass mainboards standoffs. Microstar International and
Asus mainboards have electricity conductive solder coated rings
around their mounting holes which are directly connected to device
ground pins, and they do not come with washers either.

You don't have to be a rocket scientist to figure out what that
means.

If what you are saying were true, which it isn't, given the contrary
circumstances, motherboard/mainboard makers would advise us to use
insulation. Clearly, we are expected to ground the mainboard at
those points. (I am speaking about mainboards which have electricity
conductive rings around their mounting holes.)

Nylon standoffs are the simple solution.

They would be, if what you're saying were true. Nylon standoffs
would be cheaper than electricity conducting brass standoffs also.

Motherboard's green solder mask is not intended to be an
electrical insulator (even though some assume so).

Electricity conductive mounting hole rings are not intended to be
electrical insulators either. The idea that any manufacturer would
use electricity conductive material for an insulator is bizarre in
my opinion.




Don't listen to w_tom.
He is not here to help or discuss, but rather to abuse people as he has been
doing for years.
Just add him to your kill filters along with the other internet kooks as
many others have done.

Static electricity to the chassis is not absorbed by a
mythical chassis capacitance, and does not damage electronic
components by passing through motherboard logic ground.
Static electric discharge causes voltage differences in the
ground plane resulting in digital ICs at different ground
voltages. As even National Semiconductor app notes
demonstrated (and NatSemi had some of the best databooks
containing only application notes), ICs are most susceptible
to erroneous operation when noise (that static electric
discharge from a human) appears on IC's ground pin. PC board
designs go to great lengths to minimize potential differences
on ground plane. For example, 0.01 uf bypass capacitors are
placed everywhere on motherboard board because voltage
differences can exist and cause computer crashes. Proper
grounding is so important (notice the many posters here that
remain in denial) that a recent trade rag discusses grounding
complexity:
http://www.edn.com/toc-archive/2004/20041111.html

But all this bypass capacitance and other PC board design
techniques are for naught when transient currents enter ground
plane on one side and leave on another. Solution is simple
and well known - especially in high reliability designs.
Logic (motherboard) ground makes a single point connection to
chassis ground. A transient to chassis has only one incoming
point and no outgoing point. Therefore no transient currents
flow through motherboard - to cause computer crashes.

Not computer damage. We are discussing noise that causes
erroneous digital operation - crashes. Computer crash avoided
because external transients (ie static electric discharge from
human) do not pass through motherboard IF motherboard is
mounted with a single point connection between logic ground
and chassis ground.

Bottom line - when motherboard is mounted with a single
conductive connection to chassis ground, then motherboard is
more resilient to external transients. This single point
ground must be located adjacent to IO slots and power
connector.

John Doe wrote:
w_tom wrote:
[insults and irrelevant credentials eliminated]
...
Make a computer systems more reliable. A connection between
motherboard logic ground and chassis ground should be single point.

I think maybe w_tom is trying to diverge at this point to talk about
logic versus analog ground. I have read about that, however it has
nothing to do with this.

With dry weather approaching, the previously posted static
electricity experiment can demonstrate the principles.

What w_tom is referring to is the idea that static electricity
discharge from you to the case could hurt your mainboard/motherboard
if it is connected through main board standoffs. The capacitance of
a computer case would likely absorb any static electricity you can
generate. The reverse is more likely true and beneficial. Unwanted
electricity generated on the main board would more easily find a way
to the case.

Again, to be clear, I'm talking about mainboards which include
electricity conductive rings around the mounting holes. What the
maker chooses to connect those points to, whether digital or analog
device ground, is up to the maker. But obviously those points are
meant to be connected to the case.

Grounding concepts in that cited microchip discussion are
same. Separate digital, analog, and other grounds with a
single point connection is done for same reason that
motherboard's logic ground is isolated from chassis ground.
Provided were examples, underlying technical concepts, and
simple experiments that demonstrate the problem. Deny it all
you want - without posting a single technical fact. Intuitive
reasoning without years of engineering training and experience
means junk science reasoning. But then, David, we have dealt
with your junk science claims previously. Without a technical
reason why, the denial is only a 'junk science' response.

So that external transient currents do not pass through the
logic ground (cause computer crashes), that logic ground must
make only one connection to the chassis ground. This single
point grounding technique - done for same reasons to eliminate
ground loops in stereo systems - makes a more reliable
computer.

David Maynard wrote:
That's a typical analog single point circuit ground, the primary purpose
being to isolate the analog section from the digital section's switching
induced ground noise; which has nothing to do with chassis/motherboard
shield grounding.

It is intuitively obvious to even the most casual observer, however,
that a 9.6 inch by 9.6 inch ground planed mATX motherboard does not
present a 'single point ground' to it's components. The point being,
while a 'single point ground' has specific uses, to then go dancing
around claiming it's 'the solution' to everything under the sun is
to not understand it.

alt.computerhardware.science-PSU

snore


"

On Wed, 24 Nov 2004 18:57:33 -0500, w_tom wrote:

In the junior high school lunch room, where basic knowledge
is minimal, the child learns how insults can replace fact.
However adults learn facts before posting. If John Doe had
basic electrical knowledge, then he would have discovered
numerous references to single point grounding. Instead, John
Doe searched newsgroups (not the web) for electrical
principals he never bothered to learn.

A John Doe educated in simple electrical concepts would have
found numerous engineering discussions about single point
ground. One from Microchip - a microprocessor manufacturer:
http://www.microchipc.com/PIC_tips_3.asp
The best way to handle the ground problem is to have different
ground systems that connect at only one point. The precision
analog REFERENCE ground should always be designed so that an
absolute minimum of current actually flows through it. In
practice this is accomplished by having all reference ground
connections terminating at a SINGLE POINT.

This is but one example. Literally every electronic part
manufacturer provides application notes that teach variations
of the single point grounding. Again, in stereo and PA
systems, the same concept eliminates something called ground
loops.

snip

I read the article and it mainly deals with analog devices and/or A/D
converters and low frequency PIC chips. While it is true that multiple
grounds can create ground loops creating hum in audio or telephone
circuits we're dealing with radio frequencies in the hundreds of
megahertz for the system bus / memory and in the gigahertz region in
the case of the processor.

What the article didn't address and is more of a concern to
motherboard manufacturers is cross talk. One example of cross talk is
noise from one set of data / memory lines at 100/133/400 megahertz
bleeding over onto another set of data / memory lines. In computer
circuitry this is disastrous. What may be a ground at DC or in low
level audio or radio circuits can be a great antenna for radiating
noise at 100+ megahertz. I'm an amateur radio licensee and I've got an
antenna that's at DC ground potential. If you measured the resistance
between the two leads to it, its a dead short and would be a short
even up to the range of several megahertz. But if is a great antenna
at 144 thru 148 Megahertz. ( Our 2 meter VHF band )

I've gone over this years ago with another person and I did a search
and found a web site of a computerized medical equipment manufacturer
( not too much room for error there ) and they stated just what I
have above and that is at the frequencies modern computer systems
operate at they have to use multiple grounds otherwise the systems
become inoperable/unreliable because of cross talk. The late 70's era
Radio Shack Model 1's expansion interface was a classic example of
cross talk. It was housed in a plastic case and radiated almost as
much cross talk inducing noise as a radio station and was notoriously
unstable. It only ran at around 1 megahertz if memory serves me
correctly.

You'd also have to ask yourself if motherboard manufacturers didn't
want the motherboards to be grounded to the brass standoffs why do
they conveniently put a couple of soldered circles right in the exact
spot where those standoffs are ? As an experiment you can take and
attach the power leads part way onto the motherboard ( so the tips of
your ohmmeter can connect to the metal surfaces ), then take an
ohmmeter and measure the resistance between those soldered circles and
the ground wires and you'll find that it's a dead short, at least it
was on any motherboard I've ever checked.

HTH

Gary