Hey folks, I've been doing this for a while with my 3d printed adapters, I posted about it in a retro stuff thread but it should really have had a dedicated thread.
You can see pictures of my adapters here: Re: Bought these (retro) hardware today
On my 486 case, I bought it specially because I could see that unlike the Inwin cases (of which I have a few), the standoffs could just be unscrewed, so adapters could sit much lower with no risk of screws causing shorts. But my 386 build has pressed in standoffs and works great.
The files can be had here if you've got a 3d printer handy: download/file.php?id=92248
Then you can make some adapters that sit the motherboard 3 or 4mm higher (with a similar riser for the card slots) without needing drilling. Personally I print them in PETG since PLA can warp at quite low temperatures.
This includes:
- The backplate for ATX > AT with that micro ATX position
- An adapter to raise up the card slots mounting surface (needs longer screws)
- Front & back mATX to AT adapters.
Beware that the adapter bracket screws attaching to the original standoff locations might be very close to the back of the board. Use small countersunk screws which are available on ebay etc, search for hot swap caddy screws (UNC 6/32 countersunk). Or put insulation on top of the screws.
For the ATX power, I just use TFX or SFX power supplies with an AT > ATX adapter, sometimes with a -5v adapter modded in. My power switch also is just converted from a regular momentary switch to a latching switch. With that said though, my 486 didn't even get a power button, its power supply has a switch on the back so I just use that, like my old XT case 😁