Disassembled some more, started cleaning it for real.
Found on the PCB that it is indeed a Qtronix QX-301HN from 1989. Also, it has an XT-AT switch, which is quite nice if I ever get an XT class machine. Pics taken before cleaning.
I've seen dirtier keyboards but this isn't pretty. Will disassemble further later on for a deeper cleaning.
It's here; it's supposed to be a Qtronix QX-301H (I've seen nearly identical keyboards online with a different name), but lost its label at some point. Needs a bit of a clean but seems okay.
To give you an idea of how old the keyboard happens to be, I had to buy one of these adapters. I used to have a couple of these in the 1990s but got rid of them in one of my moves.
Bits&Terminal Jeff
Kari Perttula