So it clicks, so I drop four dollars on it at the Goodwill.
It reminds me somewhat of the PDC-101 board on keyboardporn, in that it's got noisy switches with vaguely ALPS-like interfaces, on a plastic backplate and a circuit board which barely covers the switches.
However, all other factors differ:
* dye-sub look keys
* big-enter 101 layout, with small backspace, quite conventional
* tiny, surprisingly attractive case.
* Switches are different not-alps-- rounded edges and a light blue colour.
The controller is datecoded late 1991, and there's an XT-AT switch. The only external label is a serial number-- i see evidence of a removed label. However, the PCB is labelled K108S.
Pics to follow