So, I'm looking for a chad box for one of these.
Any leads would be helpful.
Good luck. In my experience they are considerably rarer than the machines.
About 20 years ago, Facit could still supply the chad box (and other
spares for the 4070). But the price then was about \pounds 30.00. I have
no idea if it's still available, but if so, it'll not be cheap.
I would sgugest getting some plastic sheet and a solvent-toye adhesive
and making one..
-tony