Same type of KBC was used from the original AT to the late pentium era. Not really 286 specific. It's just an Intel 8042 uc with a ROM burned to it

Cool, cheers. I got myself lost deep in old vcfed threads and YT vids, and came out with the impression that there was something different back in this era. Guess not! I also got the impression that it was easier to find compatible replacements in later systems. But perhaps that's just because there are more of them around.

Which comes back to the question... what are your options if one dies?

I've managed to pick up a replacement with the same part number, but there's no telling how it's programmed until I can test it.

I have found there are some that boast fast and turbo i appologise for not memorising brand but fastkey is a brand 🤣 so not all keyboard controllers were created equal.

Yes, different firmwares support different extra features (like mentioned turbo, ps2, combo with ps2 mouse), different pin mappings (A20 command might switch different pins).
One example https://alexandrugroza.ro/microelectronics/sy … sbmc/index.html
"You absolutely need an AMI KB-BIOS-VER-F keyboard controller in order to make use of PS/2-mode with the AMI BIOS dated 8/8/93. However other BIOSes can use different keyboard controllers. For instance, VIA VT82C42 which is readily available on multiple sources. Or other PS/2 capable keyboard controllers ICs such as HT6542B. I think you can also use one of the original 8242 microcontrollers. But you need to source one with PS/2 compatible software written inside."

"By examining the BIOS identification string that I decoded earlier in this article, we can see the BIOS expects a keyboard controller with an H version. Also it appears that the BIOS would not support PS/2 mouse signals as P22 and P23 of the keyboard controller are blocked. Let's just do a quick check on the keyboard controller that was originally present on the mainboard that this particular BIOS was tailored for. It is a JETkey V5.0 branded chip. I read somewhere on the Interned that these ICs are virtually Samsung Electronics ASICs."

"Adapting an 80386DX ROM BIOS for PS/2 Keyboard and Mouse Support" https://alexandrugroza.ro/microelectronics/es … bios/index.html