I finally gave up on that yesterday and decided to do what angel-tech did here: viewtopic.php?f=54&t=2264
Once the top board was off (2 screws), I connected to the 96 pin header on the SmartStep/3 board with some Futaba J connectors from my r/c model days. I followed the pin guide here: viewtopic.php?f=15&t=2119 I removed the black wire pins from the connector shells and plugged them onto the gnd pins separately. This leaves the red/white wires in the shells for the step/dir signals on pins 14 & 15.
I cut the end off an old parallel cable and matched up the wires using the pin assignments I found here towards the bottom of the page: https://www.hobbycnc.com/products/hobbyc ... oard-kits/
Yes, I know there's no isolation in my parallel cable hack but I didn't want to spend any cash until I found out if this thing works.
I drug an old PII 400 down out of the attic to sacrifice its parallel port in case I wired something wrong. It has W2K installed so I went here: https://www.bootdisk.com/bootdisk.htm and downloaded their custom DOS boot disk without ramdrive. I downloaded TurboCNC (DOS shareware) from https://www.dakeng.com/turbo.html and installed it. After setting the step/dir pin assignments in TurboCNC's Configure screen it all works great!
I still have to get the spindle motor controller working and hook up the limit switches but I'm a very happy camper today!
I wish I could say I am smart enough to have figured all this out myself but Mr. Evan Williams of Canada, a fellow member of the Homeshop Machinist forum held my hand throughout the process. Thanks Evan!
