Hi all.
Is it enough to just remove a 486 AT motherboard from an old case and put it into a brand new case with a brand new ATX power supply?
Are there any pitfalls to watch out for?
It isn't as smooth as that.
You will likely need an adapter for the PSU, an AT-ATX backplate, you need a suitable PSU with enough power on the +5V rail and you need to clarify your -5V needs and address them somehow, if required.
Retro PC warning: The things you own end up owning you.
A-Trend ATC-1020 V1.1 ❇ Cyrix 6x86 150+ @ 120MHz ❇ 32MiB EDO RAM (8MiBx4) ❇ A-Trend S3 Trio64V2 2MiB
Aztech Pro16 II-3D PnP ❇ 8.4GiB Quantum Fireball ❇ Win95 OSR2 Plus!
In addition to the great advice so far, you will likely also need to swap out the soft power button the the ATX case for a latching unit.
Alternatively, there's also this project - PCB to Use AT Motherboard with ATX PSU and Case
