That keyboard is part of an MSX computer, incompatible with PCs.
I haven't found whether it is mechanical or not, but it very likely is. At that time (1985), keyboards were either chiclet or mechanical, and there were many kinds of switches, most bad.
The computer in the ebay picture is this one:
"Pioneer Palcom PX-7"
http://www.old-computers.com/museum/computer.asp?c=301made in japan in 1985, incompatible with PCs (like a commodore or Apple ][ )
According to the wikipedia:
https://en.wikipedia.org/wiki/MSX#Keyboardthe keyboard scanlines for MSX computers were probed by the computer, with a parallel interface very very different from PS/2, which is serial. Though I don't know the Pioneer Palcom PX-7 and it might be different.
Cheers!
.KeyHopper.