Just a little update as I’ve only done a little bit of work on the Z80 this evening;

The LED matrix board now plugs in to my Z80 backplane!

Nothing too fancy, just a 16 way DIP socket on a bit of Veroboard with right angle pins and a bit of 16 way ribbon cable.

Sadly, the rainbow coloured ribbon cable you saw in the photo a couple of days ago was 14 way.  So although it looked much nicer, I would have had to drop one of the data lines and the IRQ line to use it.  (It was tempting though!).

Still no delivery from OSHPark though.  Now only got a week left to fill all those empty slots on the backplane!