Transforming an Amiga 500 (using only the case)

[Zac67]

It's not easy to use the original keyboard on a PC - but it's possible. There's been some adapter available somewhere, but I can't remember the name/make... (Maybe it was only for A1200 keyboards?)

Without a proper adapter it's not possible, since the scan codes are completely incompatible.

[...] Yeah - found it. It's Keyrah - no, that's only for A1200 KB, too...

[Zac67]

The A500 keyboard includes the controller chip and has a serial connection to the MB, the A1200's KB controller sits on the MB and the cable runs from the controller to the key matrix.
The A500 keyboard might be modified if you remove its controller and connect the matrix to Keyrah - but you'll never know until you try. Probably quite a bit of soldering required.