Light Machine Corp. Benchman XTr (retrofit)

Be careful using another ATC board. Although the hardware is the same, the onboard code may be different based on the configuration of the donor machine. U4 and U14 should be the same, but U6 will be different. Check the printed label on each to verify. It is unlikely (but not impossible) your short at J8 would have damaged U4, it is powered by onboard generated +5V. If you actually did damage U4 by the short, I would suspect that a lot more than just U4 has been damaged.

If you destroyed the COM1, did you reconfigure the software to redirect ATC commands to the new COM port? Did you ever get the onboard ATC diagnostics to operate?

Is this machine running LinuxCNC? I think I would be looking to shift ATC control to LinuxCNC (so that I have hardware and software that I understand).

You can do the sequencing in G-code, so no need to learn a new language. There is an example here in one of the Vismach virtual machines:

github.com/LinuxCNC/linuxcnc/blob/master...hange/toolchange.ngc

Bad news. I searched the shop and those boards are missing. I found two of the other boards but not the ATC boards. I can only assume they are victims of a shop clean out. Sorry to have raised your hopes without having the boards in hand.

Bummer. But thank you, Steve for offering and looking for those. I do appreciate it.

I did reconfigure the machine to use COM2 but I haven't been able to figure out the onboard ATC diagnostics. In the schematics you posted J7 is the Host interface and shows 8 wires going back to the MU board, but mine only has two wires. Is J11 the connector for the onboard diagnostics? My pcb has the holes at J11 but no connector. I will post a picture.

The machine is not running LinuxCNC. I spent a good deal of time getting it to run on the original software with the Nextmove PC card and I would hate to see that work go to waste, but I might have to go that route in the future.

Here's my ATC board:

J11 was only used for development. We never removed it for production boards.
J7 should only have 2 wires to it, Pins 1 and 8. It is used only for reset of the toolchanger.

All communications to the ATC happen through J2.
If you set up Hyperterminal,you should be able to get into the onboard diagnostics.
<ctrl> H, <alt> H, <shift> H, or maybe <alt><shift> H, I do not recall.

J7 was only a way to access U4 for programming and for the Toolchanger RESET function.

I have my data files from that time, but I do not have my notebooks.
Everything is what I can remember, but even that is suspect.