Aren't AT boards supposed to come with plastic standoffs?

I've got a small AT motherboard in an AT mid-tower case - all of the plastic standoffs are installed, but as it's a shorter board it doesn't reach the second screw hole, much as the OP - and so it pivots around the screw hole and never really feels secure.

Haven't found a good answer either.

I've previously just drilled (7/64") and tapped (6-32NC) new holes into the tray and fitted my own standoffs (brass, nylon, whatever) where needed.

I recall having that problem with one of those tiny 486 PCI motherboards I had during the mid 90s. The mounting holes in the board only matched with one brass standoff in the case, while the rest had to use those plastic standoffs. The motherboard on its own did not stay in place when the case was put in the proper vertical position, since it pivoted around the screw as LHN91 said.

If I remember correctly I did not do anything about it, since the expansion cards helped in holding the board in place after everything was installed, but it always bugged me anyways.

Maybe if you post pictures of your specific case we can figure out a solution, it would be a shame if you had to get rid of an AT case since those are becoming very hard to find in many places.

On some AT boards/AT-case combinations, you can use up to 4 brass standoff's. Others combinations, you can only use 2 and sometimes only a single brass standoff. It all depends on what you have and what you can get the hands on.

For nylon standoffs, you have to use these kind of things, that I have attached a photo of.
They are a bitch to work with, yet when they have slided into the groove in the case, they are surprisingly good.
They make a good stable mounting of the motherboard. On a few places, you can use those that only "rest" on the metal.
You know... Those that do not have a knob on the bottom, only a flat plate (the standard ATX era standoff's)
If you have trouble with cache memmory taking up the place, were a hole has to be (typically top right corner),
you can just used some electrically insulated stuff. (Those pads you put under a chair in order not to scrape the floor)
They typically come with glue on one of the sides, and I have used two of them (one on top of the other) in some
of my builds. I have attached a photo of them as the bottom photo.

EDIT:
Regarding the nylon standoffs, they come in at least two different sizes/hights. As well as brass standoffs.
Just check that every standoff's in you'r case, have the exact same hight. I have used different standoffs in the past.
And they will only make the motherboard bent slightly, wich is enough for not post'ing sometimes.
And they can result in expansions cards not being able to be inserted correctly, because they will sit too high at
the bracket you secure with a screw, and when you tighten the screw, the card will sit at an angle.
That will make bad contact in the slots and eighter make an unstable system or the card will not work.

Pictures I can do!

Here's the back side of the plate.

As you can see, there's NOT much to work with here as every single hole on the motherboard has a standoff in it, they're just all plastic keyhole types. If you look at the bottom edge of the picture, you may have spotted the board edge standoff along with the snap-in spacers--my case came with two of these and I'm sure I'm not using them as intended, but it helped the wobble quite a bit. (top side) Didn't solve it, but it did help.

That's almost enough, but not quite. If I had one more fixed screw it would probably solve the wobble problem enough to allow me to seat the AGP card once and have it not be finicky.

Otherwise I've got hybridizing the case otherwise well in hand with everything I intend to do planned to be reversible: I've installed a momentary AT-style ATX power switch works well, I've got parts for putting a 2pin connector on the turbo switch and powering the 7seg display, and I'm almost certainly replacing the internal rat's nest front panel wiring harness with a modern ribbon cable. The only reason I haven't done that yet is that I'd like to find a breakaway version if possible and those aren't common anymore. This case has the turbo, reset, and LEDs affixed with hotsnot, so it'll be easy to remove and replace them.

The edges of the case are sharp--ask me how I know naturally) and the plastics are merely painted black, but it looks decent enough and can be a really nice case for a vintage system when I'm done with it. So I'd appreciate any thoughts you guys might have.

Thanks! 😀

Edit: Dropbox image links are only valid for a short time apparently to prevent what I did there. I've gone back and replaced them with links to the dropbox page. *sigh*

Seems that you can't post images that way from Dropbox. I'll edit.

iKarith wrote:

Seems that you can't post images that way from Dropbox. I'll edit.

Yeah, there might be some plugin for phpBB that automatically scales images from outside the forum, but we don't have it.

Either use VOGONS (phpBB) ability to attach and embed your images (using VOGONS for storage), or use some photo hosting site that offers thumbnails of the photos you upload as well as the originals, or scaled down your photos on Dropbox.

Of the photo hosting sites, I recommend Imgur: their thumbnailing markup for BBCode is easy to memorize: Making clickable embedded images using Imgur image hosting service

I recently picked up AT case that used to have rubber pads that held the motherboard in place and stopped it flexing in situ, however they had completely turned to a messy white paste (why?) and had to be removed. Now boards in this case flex when you insert/remove components.

The above post now has links in it to the pictures. They're large, but in this case that's probably for the best on at least the close-up of the standoffs.

Errius wrote:

I recently picked up AT case that used to have rubber pads that held the motherboard in place and stopped it flexing in situ, however they had completely turned to a messy white paste (why?) and had to be removed. Now boards in this case flex when you insert/remove components.

Flexing of the components is often a problem when you don't have enough standoffs, and my experience with later baby AT designs is that you never do. What you can do is pick up some adhesive rubber feet. A search at Amazon for "3M bumpon" or even just "rubber feet adhesive" turns up candidates quickly. Get some a little taller than you need if you can't find the exact size and shave the bottom off the feet with a utility razor knife. Then just stick the adhesive side to the baseplate where you want it and the motherboard will sit right on top of that without flexing. I don't think it will necessarily solve my problem because I need to actually secure the board in place better, but it might help your issue.