Jupiter 8 w/ Encore MIDI not sending

Hello. I own a 14-bit Jupiter 8 with an Encore JP8MK MIDI kit.

Jupiter 8 circa 1982, 14-bit
Encore FIrmware 5.1

The functionality of the kit is mostly responsive. I can set MIDI channels, store patches in the secondary bank of 64, send patch dumps from the unit to a DAW successfully. Additionally I can SEND MIDI information to the instrument and it responds/plays appropriately.

BUT - I cannot send MIDI note data FROM the instrument (although as I mentioned, I can send syses dumps from the Jupiter to my computer).

What can I do to further troubleshoot this issue? I have performed a warm reset with no success.

Anyone know of any test routines I can perform before I dig into my machine and start checking Encore wiring?