use of Insulating Washers

[Geek-9pm]

For reference.

http://en.wikipedia.org/wiki/Pizza_box_form_factor
Pizza box form factor
From Wikipedia, the free encyclopedia
The Macintosh LC's typical "pizza box" case
In computing, a pizza box is a style of case for computers or network switches. Cases of this type tend to be wide and flat, normally one or two rack units (1U or 2U, 1¾ or 3½ inch, 4.4 or 8.9 cm) in height, thus resembling pizza delivery boxes.

http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=1366
The pizza box is a plastic carapace now, corrugated for stiffness, a little LED readout glowing on the side, telling the Deliverator how many trade imbalance-producing minutes have ticked away since the fateful phone call. There are chips and stuff in there. The pizzas rest, a short stack of them, in slots behind the Deliverator's head. Each pizza glides into a slot like a circuit board into a computer, clicks into place as the smart box interfaces with the onboard system of the Deliverator's car.
(Read more about the smart box by Neal Stephenson)

[patio]

***sigh***

[Geek-9pm]

Thank you for you observations, BC_Programmer.
A volt ohm meter can be used to test for continuity and resistance. (References upon request.)  Using a VOM requires understanding, previous training and common sense. If there is continuity between two points, that simply means there is simple electrical  connectivity.

The existence of a electrical connection does not reveal how it is being used. Electrical power [low frequency] goes from a source directly ton the object and then returns directly. It does not take side a trip to explore a cul-de-sac.

A cul-de-sac (literally "bottom of bag") is a word of French origin referring to a dead end, close, no through road (UK, Australian and Canadian English) or court ...http://en.wikipedia.org/wiki/Cul-de-sac

Intel mother boars, as well as Gigabyte and many others, have hole patterns explicitly fabricated as ground connections. What you do with them is up to you. Using as a replacement for a power return is never recommended ever.

More questions?

[BC_Programmer]

Intel mother boars, as well as Gigabyte and many others, have hole patterns explicitly fabricated as ground connections.

More questions?

At the risk of sounding slightly repititious, I'm going to once again ask for some references that back up this claim.

[Geek-9pm]

Do you have auto cad or similar program? In the PCB electronics library you wail find a specific template for doing a mounting hole that has solder points and feed thru points for the express purpose of making secure connection  to a screw, post or washer that covers the hole.  If no connection is wanted, you just specify a hole in the PCB with no trace pattern and no solder mask.

It has been almost ten years since I did any PCB work and I no longer have a electronics template or any CAD on my computers. 

I showed you a photo. Do you need the actual template ton to recognize what nit is?

Maybe somebody reading this  has  a PCB  layout program and will explain what a mounting hole template looks like and what i is used for.  The template has three parts to it. The copper trace, the silk and then hole-through. It is a bit of a bother to use nit just for decoration.

[BC_Programmer]

I'll interpret that as a no, then.

[Geek-9pm]

No, you prove that it not a grounding hole. You have never given any proof that these holes are not grounding holes. You do not know what they are for. You don;t want to know. You make some non relevant reference  to some other issue and claim that constitutes a logical proof of what you imagine in your day dreams.

Please, prove that it is not a place to make contact with the case of the computer. Tell us please what is it? What do you see? Do you know what a motherboard bottom looks like? Have you ever looked at mortarboard before you install them. Of course not, you install them on any moonless nights so the light of truth will not destroy your fantasies.

The only reason I post this is not to correct you, which is impossible, but to warn others -
not to drink that strange Kool-Aid you have.

[Computer_Commando]

Good idea. And I did. And the results suprised me. Testing between all mounting locations on my Intel D845GVSR yeilded a result of "0" ohms resistance on 20k DVOM scale between all mounting locations. I don't see where they are connected to the circuit traces, but they are certainly connected somehow. ...

Only when mounted to the chassis, they are connected to each other & the chassis.  They don't connect to traces or layers in an ATX motherboard application, but could in other "custom" applications.

No, you prove that it not a grounding hole. You have never given any proof that these holes are not grounding holes...

I qualify myself as an expert witness.  I used to design computer circuit boards for a living.  You can call them grounding holes, you can call them mounting holes, or whatever you like.  Grounding is not shielding & is confused or mislabeled by many so-called experts.  The fact that it's in a PCB library means nothing.  If the designer pulls a grounding pad instead of a mounting pad, it matters not & indicates nothing.  When the board is mounted, the screw head connects the solder pad to the case.  So what?  It doesn't connect anything else on the circuit board to the case, except for the shield of one of the connectors, IF the specification requires or recommends it, & most specs do not.

It may appear to be a grounding hole, but it does not function as one!!!

[Geek-9pm]

Thank you Computer_Commando,
You answer makes sense. If it is not connected, it does not matter what it looks like. If i not connected, then the insulating washer would only help protect from a mount that off center and threatened nearby traces.

I appreciate that you have done PCB work, so  you understands what I mean. The pattern in the photo above would or should be used when a connection is wanted. It requires trace, solder mask, silk and hole through. As you know, hole-through is a significant cost, but not excessive. And yes, the artist might have used it for nothing.  But that is not was n happened. He put in in the net. Every one has conductivity intrinsically.

Yes, the term 'ground' is overloaded. Thee is a set of traces and wires the tie into the power connector. The designation of that set is called GND in the specs.  I am referencing to that set of traces and wires, visible or not, that  run to the GND group of the power connector.

With the board removed, nothing connected to it, on a wood table, there is continuity from the GND to several points on the motherboard.

Personally, I have seen some  PCBs that nave only a hole and no trace, solder or hole through. Just a hole in the board. But to date, I have not yet found any motherboard with the obvious pattern that did not have a connection to the trace/wire group  is called GND at the connector. Call it what you want,  it has conductivity to the group when the board is out of the case. I belie I said that earlier. All eight holes I in the first picture have continuity when the board was out of en case.
I am going to check every motherboard I have to see if that hole pattern is ever used without conductivity to the GND group.

[BC_Programmer]

All eight holes I in the first picture have continuity when the board was out of en case.

you said: these points act as:

"the entire common return of the entire board, memory, PCI, CPU, I/O ports, including USB. the whole thing."

[Geek-9pm]

Thank you. Yeah, thaht was what I siad. All boards I have tested so far, out of case, on the table, have electrical continuity from the solder ring inside mount hole hole to the other points on the motherboard that electrically connect to the power connector GND. This GND thing electrically ties into parts of the memory, the CPU, the PCI and other points on the Motherboard. Must be like a spider web in there.

The ATX specs say there has to be reversal connectors in the Molex that are GND. Boy, did they get that wrong! They don't do anything, barbecue tGND  tie into the mounting holes. which are only used for mounting, never anything else. Somebody tell them the GND are useless.

Somebody said the motherboard has no connection to the mounting holes. If that is true, then then logically parts of then CPU, the PCI, the memory and the GND connectors have no purpose. They do not don't anything because expertise have told us that the muting rings have no connection to the motherboard.

So therefore, Intel, Gigabyte and others are running a lot of unneeded wires inside the motherboard. Now if can get the vital information to them, perhaps they can build better motherboards and stop just messing around with their fancy PCB auto-router tools. They need to hire some people that know what they are doing.

Good thing we have this post! We are making progress! Using the simple rules of logic, we do not need any of the black wires in the power cable harness. Barbecue they are part of then useless network the ties into the mounting holes. Think of how this will simplify our new builds!

{Had to us the green color because wry sarcastic color was all used up.}

[lectrocrew]

The mounting holes will be conducive through the case.. unless it's plastic,

I tested my board with it not mounted in a case.

Testing on a unused AMD board I have and there is no connection between any of the mount points.

Are you saying there is no continuity (infinite ohms resistance)?
or
Are you saying there is no connection between the mounting hole and the traces on the board?

[lectrocrew]

Only when mounted to the chassis, they are connected to each other & the chassis.  They don't connect to traces or layers in an ATX motherboard

Not true in my case. My test were done with the mboard not mounted.

[lectrocrew]

But it will work without them. It will work in a Pizza box.
(Anybody remember the Apple Pizza box ad?)

I guess my next test will be running the mboard in a pizza box.

Quote
http://en.wikipedia.org/wiki/Pizza_box_form_factor
Pizza box form factor
From Wikipedia, the free encyclopedia
The Macintosh LC's typical "pizza box" case
In computing, a pizza box is a style of case for computers or network switches. Cases of this type tend to be wide and flat, normally one or two rack units (1U or 2U, 1¾ or 3½ inch, 4.4 or 8.9 cm) in height, thus resembling pizza delivery boxes.
Quote
http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=1366
The pizza box is a plastic carapace now, corrugated for stiffness, a little LED readout glowing on the side, telling the Deliverator how many trade imbalance-producing minutes have ticked away since the fateful phone call. There are chips and stuff in there. The pizzas rest, a short stack of them, in slots behind the Deliverator's head. Each pizza glides into a slot like a circuit board into a computer, clicks into place as the smart box interfaces with the onboard system of the Deliverator's car.
(Read more about the smart box by Neal Stephenson)

I thought you meant a cardboard pizza box lol. 

But I did run the D845GVSR mboard with all the mounting screws removed and the board resting on rubber grommets (insulated from the case). It started up and ran just fine - no change from being mounted. So, although all the mounting holes do test 0 ohms continuity between them when the board is not mounted, there seems to be no need to "ground" the board to the case.

[Geek-9pm]

This thread is now solved.
All we need now is somebody to tell us what the answer is.   

Mac and PC ad Pizza Box   
http://www.youtube.com/watch?v=e32OEku5el8

PIZZA BOX COMPUTERS   
http://www.youtube.com/watch?v=inph0y_LxQs