Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

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Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby bergqvistjl » 2019-3-15 @ 16:01

So I've got myself a Baby AT Mobo (Jetway J-542B).

Anyway, when mounting it in my new old stock Desk Top AT case (which has standoff holes for ATX, AT & Baby AT), when screwing in into the standoffs in the correct positions, none of my expansion cards fit - they're about 1 or 2 MM off - to the extant that if I removed the brackets on all of the cards, that would give them enough room to fit.

So what i've done is instead of screwing the mobo into the standoffs, just left it resting on there while moving it back slightly so that I can install the expansion cards - meaning that the only thing holding the mobo still is the fact that the expansion cards (GP card, 2x PCI & 1x ISA) are screwed into the case using the expansion slot brackets.

Is this safe? The motherboard appears stable, its not moving of its own, and I don't have a massive CPU cooler or anything like that.

My ATX board fit perfectly in the case, I should add.
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby bofh.fromhell » 2019-3-15 @ 17:23

This is also my experience with AT gear.
I suspect that the spec was not as clearly defined as ATX is so you get variations.
Whats a potential problem is that motherboards also use the mountingpoints as grounding.
Tho I've seen AT boards mounted with one screw and the rest just plastic standoffs.

So I dont think its anything to worry about.
But if I were you I'd place a whole bunch of rubber standoffs under the board "just incase".
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby retardware » 2019-3-15 @ 17:33

Sometimes such is caused by cases being not fully straight.
Also possible is that the mobo manufacturer did not keep the AT standard dimensions, which happened quite often.

bofh.fromhell wrote:Tho I've seen AT boards mounted with one screw and the rest just plastic standoffs.

This is okay, as the original IBM AT mobo rested on plastic standoffs except for two screws.
Due to the smaller size of baby AT mobos, these can be only fastened with one screw (if at all, see my experience)
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby bergqvistjl » 2019-3-15 @ 18:42

Well not a single screw is in alignment in a way that would let me use the expansion cards properly. They're in alignment with each other, just not the expansion slots
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby bakemono » 2019-3-15 @ 23:33

I wouldn't let the board rest against a metal standoff. That could produce a short circuit where they are touching. Put some kind of insulator in between at least.
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby Tiido » 2019-3-16 @ 00:56

I have one case like that. I make sure the metal standoff can in no way come in contact with what it shouldn't. In one spot I had to apply some kapton tape to make sure things were isolated.
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby bergqvistjl » 2019-3-16 @ 09:47

What could I use as an insulator? Will PVC Insulation tape covering the standoffs do?
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby retardware » 2019-3-16 @ 17:57

PVC insulation tape not recommended. Does not stick firmly, is too soft (can be pierced easily).

1. clean surface with IPA swab.
2. As @tiido said, cut some kapton tape into form and insulate the area with it. Better two patches to make it more resistant.
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby PARKE » 2019-3-16 @ 19:10

bergqvistjl wrote:What could I use as an insulator? Will PVC Insulation tape covering the standoffs do?


You might consider finding nylon standoffs.
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby Thallanor » 2019-4-10 @ 20:43

bofh.fromhell wrote:Whats a potential problem is that motherboards also use the mountingpoints as grounding.

Grounding would be my biggest concern here too.
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby Merovign » 2019-4-11 @ 06:52

Is there another motherboard available to test the layout, in other words to find out whether it's the case or the mobo that's out of spec?

I'll trade you a minitower for the desktop case. ;)

If you don't have another motherboard you could technically mark the board holes on paper and then the case and then mark the case mounts and see how far off you are. Maybe there is some combination that will get you close enough.

Also try placing it with an expansion card or two in place to make sure the mobo is where it's supposed to be, I've seen combos that just wouldn't line up properly.
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby appiah4 » 2019-4-11 @ 07:28

The leftmost screw hole on most AT motherboards is not round but elliptic and that allows for adjusting the orientation via shifting and rotating so that the other screws align with the holes; have you looked into this?

I would wager that your case and not the board is the one out of spec here, though..
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby PARKE » 2019-4-11 @ 15:15

Thallanor wrote:
bofh.fromhell wrote:Whats a potential problem is that motherboards also use the mountingpoints as grounding.

Grounding would be my biggest concern here too.


My suspicion is that the effectiveness of grounding motherboards via standoffs is fairly overrated. The board is already grounded via several connections in the 20/24 PSU connector and subsequently via the wall socket to everything that is grounded on the planet. There are cases and test rigs based on acryl plus a number of people here regularly test their mobo's on cardboard boxes.
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby Thallanor » 2019-4-11 @ 15:38

PARKE wrote:My suspicion is that the effectiveness of grounding motherboards via standoffs is fairly overrated. The board is already grounded via several connections in the 20/24 PSU connector and subsequently via the wall socket to everything that is grounded on the planet. There are cases and test rigs based on acryl plus a number of people here regularly test their mobo's on cardboard boxes.

It is certainly possible! I remember reading somewhere though that it had something to do with grounding differential or similar, between the case and the PSU's chassis. But I could be totally out to lunch on that one. I mean, I've run (and I presume many of us have) motherboards just sitting in a cardboard motherboard box and have had no issues. :)
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby PARKE » 2019-4-11 @ 15:49

Maybe, Maybe with capital M, it also depends on the mobo. But if in doubt it is easy to make a couple of extra ground connections via wires to the case when a mobo sits on nylon stand offs.
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby beastlike » 2019-4-13 @ 01:06

Warning:

I've had a bad experience with this - be careful WHERE the standoff lands - I lined up a motherboard onto a case that was set up differently, and I believe it caused a short
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Re: Baby AT mobo slightly out of line of standoffs - is it safe to just rest it on them?

Postby bergqvistjl » 2019-4-19 @ 14:19

appiah4 wrote:The leftmost screw hole on most AT motherboards is not round but elliptic and that allows for adjusting the orientation via shifting and rotating so that the other screws align with the holes; have you looked into this?

I would wager that your case and not the board is the one out of spec here, though..

All 3 different cases I have with AT connectors on have the same issue, regardless of how I utilise the left-most screwhole, unfortunately. All other (ATX) mobos I have are fine.

I covered the standoffs with the appropriate tape and it was fine.
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