The Labtam 3000 apparently needs a second 8086 card installed to boot CCP/M-86.
That make 3 Multibus cards in total to run this OS:
- the Z80SBC handles the floppy drive and bootstraps the others
- the first 8086 VDU/COMM card drives the video and serial ports (and I think keyboard)
- the second 8086 CPU card runs 8086 software
The 8086 card is actually the same hardware, with DIP switches configured slightly differently and different firmware. Anyway, now that it's reporting an actual problem instead of just waiting for something which never happens, it should be possible to progress further.