I got the 4 axis version of this board. The same one in the first photo. It seems working fine for me even without mods. I've tested it with a MaxNC machine and it gave me faster speed than I would ever need. I've hooked it to a NEMA17 stepper (400 step / rev) driving a belt and it could give me 1000ipm with 12v PC power supply after I by pass the opto that drives the step signal. Without by passing this opto it does loose step at some speed (which I don't remember what speed, but it was quite high). I have to try changing the osc capacitor to see how it behaves.

When I try this board on some motors I have, I could not increase speed no matter what I try. This motor is rated at 6v 1.2A. I guess it's not compatible with this board, because the other two motors are working fine? Anyone has any idea on this?

Thanks


ps. I would like to thank the original poster who started this thread (Lasik2025) and everyone who contributes to this thread. Your posts are very educational and informative.