I wasn't bothered about having an original one and didn't think it would be much of an issue getting a old ps/2 keyboard running on the system as two different people have made adapters. Unfortunately the first one wasn't ever released publicly and the other one is available but at a price of $100 or $125 if you want a used ps/2 keyboard too.
As much of a bargain as that is I went looking for an alterative, ABI didn't help matters by using a top quality cherry made keyboard. As now in 2016 you've got keyboard collectors (yes that's a thing apparently) buying them up. Not only are they driving prices up but they butcher them by pulling off all keycaps, don't ask me what they do with them I have no idea.
While waiting to hear back from a keyboard collector who had one (minus all the keycaps of course) I came across this keyboard listed as a 'vintage studio keyboard' on ebay. As it had the correct layout and number of keys I took a chance on it and ended up winning it dirt cheap.
After receiving it and cracking it open I confirmed it had the correct cherry pcb. As this keyboard was used for different equipment I had to make a few changes, two 74LS08 needed to be populated along with a 1k resistor and a couple of jumpers needed to be changed to change it to serial from parallel. Also the data on the 8749 mcu had some incorrect character data compared to the original keyboard.
A big thanks to my friend Equites on ukvac who was willing to dump the 8749 in his original keyboard and I now have a fully working boardmaster keyboard for less than £10.
While searching I came across this pdf datasheet which has all the info you'd need to replicate the keyboard if anyone else happens to need one and aren't lucky enough to stumble across a cheap one on ebay. :)
