Dumb & Stupid MB question

engrbill47

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Aug 14, 2001
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I am currently building a new PC for my dear wife. And I have what maybe the Tom's Hardware Most Stupid Question. When you are physically mounting the MB to the floor of the case, do those little fiber washers need to be placed under the heads of the mounting screws? I apologize in advance for my simple question, but it's been a while since I last positioned a MB in a case and I don't want to bend down (I'm officially a geezer[62+]) and disturb the dust bunnies that may have organized since I last mounted the MB in the PC that I am using to write this plea. :??:
 
Solution
Ahh - I mis-spoke, but we mean the same thing. I believe (but haven't dissected a MOBO [I've been tempted though {expensive experiment though, these days!} - really miss the Z80 days, when for $5 and twenty-five cents postage, you could have an actual schematic of your board!] to be sure) that these MLBs have a layer thats just a 'case grounded' 'shield' (am used to troubleshooting screwed up shielded twisted pairs, so I think of the shield as a ground-plane, but, you're right, the signal/power ground is a different animal) for the signal traces... I always do this:
0043r.jpg

just to ensure that I get a 'single-endian', properly 'branching' case ground. Probably just a mark that I'm too...
nah dont need to be - its good to have those points earth out to the case, and they wont stop anything since the same contact points are under the case

aslong as you have it all mounted correctly thats all that matters, dont short the board on the back pannel
 

TheDraac

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Feb 1, 2008
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What...?? Are you Dumb??? Or just Stupid??? LOLOL :)

Just kidding..... those fiber washers are not necessary. I haven't used them on years. BUT.... if for some reason the MB manual actually says to use them, then by all means use them.

Otherwise, no.
 


See my sig and agree with it :)

When you are physically mounting the MB to the floor of the case, do those little fiber washers need to be placed under the heads of the mounting screws? I apologize in advance for my simple question, but it's been a while since I last positioned a MB in a case and I don't want to bend down (I'm officially a geezer[62+]) and disturb the dust bunnies that may have organized since I last mounted the MB in the PC that I am using to write this plea. :??:

I'm catchin up to you (54+). Here's the deal....the mobo holes are of two types...metalized and non metalized with the latter getting rarer and rarer these days. Metalized ones are easily recognizable by the metal ring around them which serves to ground the case to the MoBo. You can just screw straight into these. The cardboard / felt washers are for non metalized holes, were you are tightening down on pure plastic circuit boardwhere overtightening would crack the board. You need two washers per non metalized hole....one above and one below which makes them a real PITA to install. However, it's been quite a while since I have had to use any.
 
I also have not used the fiber washers in years (for at least 10 builds).

And if I take after my mother (she's 82 now), I have a few more years before I reach geezerdom (I'm only 63). About 15 years ago, Mom (lives in Maine) slipped on ice bringing firewood in. Cracked a vertebrae. Ended her snowmobiling days. :(
 

bilbat

Splendid
If you'll take a close look, you'll see that there are a number of radially oriented solder pads surrounding the mounting holes - they are to get good contact to establish the MOBO's 'ground plane' - you don't want to insulate them, screws with the board's proper operation!
 

tcsenter

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Jun 18, 2008
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The mounting screws and holes are never connected to the motherboard's ground plane. This would be extremely undesirable, as you'd basically be creating a floating ground out of your chassis, which is never a good thing.

You could use non-conductive (plastic) or conductive (metal) mounting hardware and it won't matter to the motherboard's operation. The only thing that conductive mounting points would provide is perhaps little more ESD protection.
 

bilbat

Splendid
Ahh - I mis-spoke, but we mean the same thing. I believe (but haven't dissected a MOBO [I've been tempted though {expensive experiment though, these days!} - really miss the Z80 days, when for $5 and twenty-five cents postage, you could have an actual schematic of your board!] to be sure) that these MLBs have a layer thats just a 'case grounded' 'shield' (am used to troubleshooting screwed up shielded twisted pairs, so I think of the shield as a ground-plane, but, you're right, the signal/power ground is a different animal) for the signal traces... I always do this:
0043r.jpg

just to ensure that I get a 'single-endian', properly 'branching' case ground. Probably just a mark that I'm too obsessive, but, I figure, can't hurt, either!
 
Solution