Oh, I see where you're coming from jacey714!
I know you must be saying:"then why did I need it in the first place?" Well, the engineers spec'd that out and they seem to be the only ones who know the reason. AKAI makes one thing clear on page 34, note2, of the MPC 4000 service manual which you can download here if you haven't done so already:
http://www.woralelandia.com/openmpc/files/MPC4000_Service_Manual.pdf that the cable has to be installed when using both cards. I don't know the technical reasons.
Well, as far as I can see, it doesn't support what you're expecting, maybe there's a workaround?
At least I'm glad it's doing what it is supposed to do. As far as functionality of that missing 8pin cable that was
very difficult to find is concerned, I haven't been able to find the "actual" function of that very cable.
Maybe emailing Japan/Akai for
this question may yield favorable results?
I remember last time, when doing the "cable" search, it was useless, but for a
function inquiry you
may actually get an answer? I hope so.
I really hope you find the answer to what you're looking for jacey714!
Just trying to help out where I can,
MPC USER GUY