This is a circa 1988 machine I am trying to revive with not enough technical info. To my surprise the control unit and the printer appear to work - but not the keyboard.

It, of course, uses multiple microprocessors - It will pass BIT diagnostics except that evidently the printer Z80 isn't talking to the keyboard Z80 so it doesn't think that the keyboard is actually plugged in. I believe that the keyboard Z80 is alive because the one-line display on the keyboard says PLEASE WAIT.

I have an operation and troubleshooting manual which covers the built-in test routines, but that stops at the "replace the keyboard assembly" stage.

So does anyone have a spare keyboard or a tech manual with schematics that I could borrow?

This is a very long shot, but you never know what someone has accumulated.