Great news, everyone! My third set of carts from MIS arrived today and they were recognized right away. These arrived empty (the others were prefilled with the Eboni-6 inkset) and Justin at MIS suggested I fill them with cleaning fluid, which I did. I didn't want to install them dry (my scale hasn't arrived yet so I couldn't mix up my Carbon-6). I added a small amount of Magenta Dye ink so's to make the nozzle check visible - the patterns were quite faint of course but visible with no breaks.
This set of carts was from a new batch they just got it. Justin feels it was not an issue on version numbers of the carts and firmware, but a physical issue, ie the chip was not making good contact with the bronze wires at the rear of the cartridge holder. I tend to agree with that. At last I'm a happy camper. Justin and Mathew over at MIS were diligent and patient to work with me to solve this problem.
I've ordered an Ohaus scale and as soon as that arrives I'll mix up some Carbon-6. Does anyone have any suggestions on how to empty the carts so the red dye doesn't show up in the various shades of grey? I can remove most of it with a syringe, and once they're filled with the various greys perhaps the remaining red will wash on through.
Anyway, it's a been a long haul and I thank everyone in the Group over the past few months as well as MIS for their suggestions and for putting up with my frustrations at times!
Regards,
Paul