OK, I've gotten a bit further now.  I understand that the 3100 only supports
mono graphics.  I have set my SPX board to the 1-bit setting, and now when
the machine boots off the floppy, it gets to:

619520+1118928+151904 total=0x1cd834 

and then stops.  I assume that maybe it is working....sitting at the console
maybe? Out the serial port?  But when I hit ENTER, I get a 

?06 HLT INST
      PC=8008F9BA

and I'm back to the >>> monitor prompt.


Anyone got any ideas?

-Darren