That's more encouraging - thanks cncsnw for taking another look!
On the mpg header, I wired into the pins for x,y,z axis select; 1x,10x,100x multiplier; wheel a,a-,b,b-;+5vdc,5vdc com. I assumed that these pins were for these connections. I saw in a post on Ajax where you said that the common for these switches should go to 5vdc com, so that's what I did - haven't tried it yet.
As far as the inputs 13,14,15 go, it seemed strange to have to lose 3 inputs just to loop a signal right back into the board, but I was following Scott's diagram for the AMC 30A8 drive, which has the exact same pinout as my 16A20AC drives and he confirmed to me on the phone, that it should be the same for my drives. You guys all know much more about this stuff than I do. I also downloaded the brain that he posted to make the diagram work, although I haven't installed it yet.
If my assumtions on the mpg header are right, I should have just enough inputs, I think. x-,x+,y-,y+,z-,z+,jog-,jog+,cycle start,feed hold,e-stop,enable-x,y,z,spindle fault. This is 15 of the 16 inputs - I hope I'm on the right track here.
Regarding the spindle fault: is this the circuit that goes through the A,B,C contacts (whichever is NC) on the inverter and do I feed it the 5vdc+ from the GPIO4D power header?
I am attaching Scott's diagram for the AMC drive as well as inserting a link to my build thread with some pics of my machine. I hope you will check it out and tell me what you think.
I'm sorry to be such a pain, but it is very much appreciated!
Thanks One More Time,