Properly grounding a motherboard - in a test environment...

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Postby beaconengr » Wed Dec 15, 2004 5:15 am

Actually, the suggested experiment was meant to be nonsensical, as the previous poster had become. You obviously have a lot of computer knowledge so i will concede that you are probably correct. However, we both know that grounding these points is not necessary for proper operation of the motherboard, since i see many motherboards mounted on plastic standoffs.
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Postby beaconengr » Wed Dec 15, 2004 5:27 am

Part of the reason for plastic standoffs lay in the actual layout of the motherboard. Some motherboards lacked insulators around the mounting holes, and metal contact -- even at the standoff point -- could actually result in a short or ground fault. You rarely see this type of mounting hardware anymore. They're a pain to install (lining them up can be tricky), and even more of a pain when you want to swap motherboards. These days, most motherboard mount points are insulated from the surrounding circuitry, so mounting on metal is now practical. Still, some cases ship with insulating washers with their metal screws, so if you've got them, you should use them.
Interesting. A google search is also controversial, and many sites agree with me.
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Postby colinJohn » Wed Dec 15, 2004 6:07 am

hmm - we could do with getting to the bottom of this one. We should start with 3 facts that are not controversial (possibly :wink:

1. The power supply provides a ground to the mobo and other powered hardware
2. The PC case is grounded.
3. If the board is connected to the case using metal standoffs and metal screws (with or without the use of insulating washers), via the holes in the motherboard which have been silvered - then the motherboard is grounded at those holes.

Now, we need someone to find a document that tells us whether those soldered holes are connected to any circuitry on the board or that they are completely independent of it. (But why then silver the hole?)

I've just ploughed through some Intel papers and got nothing but a head ache. I can't back this up with a quote yet, but Scott Mueller the God of 'Upgrading and Repairing PCs' 16th edition says they are ground pads - it would be cool to call him on it. :mb_duel2::
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Postby video » Wed Dec 15, 2004 6:15 am

Well, regardless of what the search brought up. When you use the pastic is when there is no grounding needed. If you do have a ground nessesary it needs to be used for proper grounding. It is always better to ground something to a chassis or a case more so then a wire to and from the power supply. You have less resistence and more of a secure methed of grounding points. They are there for a reason, in the design of the unit. No matter what you're told. I have been down this road so many times that, all I can say is good luck with your methed and in trouble shooting your system. Nothing ment here to bring up arguing in the future on this, Information is, it's just who is on the other end posting, I mean who is it that writes the do's and whatnot, the best way to find out for yourself is learn about how things work and what way they are designed to work. Just because someone builds a computer into a toaster, does not mean it IS correct. I just dont and will not aggree to the methed of taking out the motherboard and testing it on a piece of cardboard and trying to troubleshoot something that can be installed correctly in the case with "all" the proper grounding points "on" the motherboard used. Right or wrong you and I and more on here will not agree on this methed. Nothing at all here ment to be in a bad way at all to you personally. :)
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Postby beaconengr » Wed Dec 15, 2004 6:50 am

Never took it personally, and i am always trying to learn, even if it means im wrong about something. I dont have a fragile ego.
However, the one thing i do know, beyond any doubt, is that motherboards work properly when not grounded to the case. Ive done it many times. There are 3 local shops that i am familiar with, and each has a motherboard set up nailed to a piece of plywood, used for troublshooting, and has had them for years. May be an accident waiting to happen, may be ready to explode, i dont know, but it works. If there is a reason that it is better to also ground to the chassis, i would love to be pointed to an authorative site, but i can promise that this will be a controversial issue according to my electrical engineers. It would also bring up the question again as to why some cases are shipped with nylon standoffs and insulating washers for the mounting screws. Anyway, i have exciting things to do. Trying to confirm that my 6800 GT has all the transistors it claims.
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Postby colinJohn » Wed Dec 15, 2004 6:54 am

well I've just had a good look at a couple of mobos.

1 hypothesis 1. - the mobo is grounded through standoffs. I can't see any circuits going to the silvered holes. Doesn't mean it aint grounded; just that I can't see how.

2 the silvered rings look like small collars, the ring have pins that go through the board and appear to hold it in place. hypothesis 2 - they could just be stregnthening devices to stop the mobo cracking if the screws are tightened too much.

I'm swaying towards 2.
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Postby Copper » Wed Dec 15, 2004 7:07 am

the main gronding of any motherboard is via the PSU. even those brass standoff provide secondary grounding, you will also find motherboard mounted on plastic standoff which provide no grounding

either standoff will provide safe operation of the motherboard
Last edited by Copper on Wed Dec 15, 2004 7:31 am, edited 3 times in total.
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Postby beaconengr » Wed Dec 15, 2004 7:10 am

the mai gronding of any motherboard is via the PSU. even those brass standoff provide secindaary , you will also find motherboard mounted on plastic standoff which provide no grounding

either standoff will provide safe operation of te motherboard

And thats the bottom line to this whole scenario. Either way works fine.
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Postby colinJohn » Wed Dec 15, 2004 7:34 am

anyone want to cut through the black wire from the PSU to the mobo connector to see if it works without one?

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Postby robprime » Wed Dec 15, 2004 9:18 am

I just got through, presumably, dealing with this issue. See my posts about repeated power supply failures.
When I examined the mobo I saw that some of the silvers were making direct electrical contact with 'pads' and obviously designed to be grounded. Why make it like that if not? Others I saw, still silvered, had an area of nonconducting material between the pad and the silver, obviously designed to not be grounded. Both types were present on the mobo I examined and on the strength of that I decided where I had to use metal standoffs and where I could safely use plastic.
So obviously this mobo in meant to be grounded in some areas and not grounded in others.
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