Old Thrashbarg wrote:

Well I've hit a couple of stumbling blocks. The case I was going to use seems to have no threads to screw in the motherboard standoffs- it just has holes with no thread, about 3-4mm in diameter.

That sounds like the old style AT standoffs... they'd usually use one or two screws, and the rest were plastic standoffs that just slipped into slots on the motherboard tray.

The plastic standoffs I'm using look exactly like the picture there, except the case seems to require standoffs about twice as high.

My 386/486 systems use these standoffs too but the actually have slots that taper down to a smaller width - so you can fit the round bit through the slot, then slide it up into the smaller part so it can't come out. This case just has round holes and they actually aren't big enough for the standoffs to fit through.

I suspect that perhaps there is some other parts of the case missing - perhaps there was another backplate or something that screwed into the bottom of the case and the standoffs slotted in there.

hi

if i understand what you mean then you suspect
that the motherboard attached to some kind of
tray which then attached to the case frame?

you may possibly be able to hack together a
replacement tray with a suitable thickness of
plywood?

bye

sklawz wrote:

hi […]
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hi

if i understand what you mean then you suspect
that the motherboard attached to some kind of
tray which then attached to the case frame?

you may possibly be able to hack together a
replacement tray with a suitable thickness of
plywood?

bye

The standoffs for an AT motherboard look like this

The long pointy bit you would slide up through the bottom of the motherboard and the standoff would lock in place. On the other end, the round bit would fit into a hole that was sort of keyhole shaped then when you had all the standoffs lined up in the holes you would slide the motherboard over slightly until it stopped. That was what held the motherboard in place against the pull of gravity. You only needed a couple of actual screws to secure it.

sliderider wrote:

The standoffs for an AT motherboard look like this […]
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The standoffs for an AT motherboard look like this

The long pointy bit you would slide up through the bottom of the motherboard and the standoff would lock in place. On the other end, the round bit would fit into a hole that was sort of keyhole shaped then when you had all the standoffs lined up in the holes you would slide the motherboard over slightly until it stopped. That was what held the motherboard in place against the pull of gravity. You only needed a couple of actual screws to secure it.

I still have some of those plus a few where i chopped off
the nipple so you could to rest it against the chassis when
there was no hole but he infers that these standard parts
are too short hence the suspicion that an intermediate
tray may be missing.

bye

sklawz wrote:

you may possibly be able to hack together a
replacement tray with a suitable thickness of
plywood?

That's an interesting idea. That's also given me an idea. I could do something similar, when I am ready to install an AT mobo inside an ATX case. I could insert a "wooden tray" in to the base of the case, and then screw metal standoffs in to the wood for the mobo. Then, I could attach the mobo to these standoffs with PC case screws.

I wonder how I can attach a wooden tray to the base of a case? On my current ATX case, looking at the PC case base area where the metal standoffs are located, you can access the underside of this metal base area if you remove the PC case's side panel. I could drill some very simple holes in to this underside base area, and then screw some screws through these holes, which will "attach themselves" to the underside of the wooden tray. That would prevent the tray from moving.

Hmm a wood tray or spacer may be worth a try, I just gotta pull my finger out and do it 😀

sklawz wrote:

hi you may possibly be able to hack together a replacement tray with a suitable thickness of plywood? […]
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hi
you may possibly be able to hack together a
replacement tray with a suitable thickness of
plywood?

This is tricky to pull off, the thickness would needs to be exactly right, one mm might mean expansion cards will either not slide in fully (loosing contact when turned on may result in a lot "hardware pain") or will slide in entirely but can't be fixed to the case properly (which may result in the expansion card sliding partially out on one side, resulting in a lot of "hardware pain").

I believe that this case needs another type of standoffs, I've only seen on my first 286 and another case I've been given some time ago, which both are desktop type. Those two cases, have about 2-3 holes for screws, and all the rest require that dfferent kind of standoff(btw, that's a new word for me. I used to call them "spacers".) That thing i'm talking about is taller than those in the picture, and has a clip on both sides, so it clips both on the board and the case. I can't find a pic on the net right now. I'll try, but if I don't find any, I'll search my stuff. Perhaps I may have a spare one to show you.

Yes I think you are correct, if you manage to find some please show me.

retro games 100 wrote:

This has given me an idea. Is it possible to buy any ATX PC case, and drill your own holes in to its base area, and then push these plastic standoffs in to them, so it can hold an AT mobo in place? I mean, the drilling precision required for the holes wouldn't be too high I guess, because there is no "screw thread" involved when you insert the standoffs.

It would still require accuracy, as otherwise the expansion cards wouldn't fit correctly

DonutKing wrote:

Yes I think you are correct, if you manage to find some please show me.

Unfortunately I don't have any spare ones. I've been searching a lot at the net, and the only thing I found is a sketch of it. Here it is :

I guess it's really old. The image comes from this site, where it says it's on stock : http://www.marcospecialties.com/product.asp?ic=69198-100 .
In addition, I didn't remember well the way the metal standoffs where you put a screw on are mounted. You just insert them into the holes, and you tighten a nut on the other side(the bottom of the case).

Ah ok I have seen those before but they don't appear to be any taller than the normal ones. I think I need something about 20mm tall to mount the motherboard properly.

Here is my collection of standoffs.

Maybe you could use something similar to what I have done with the rightmost(standoff into standoff with washers to adjust for height) and a nut on the other side.