[Connor]

I doesn't fully modify my board yet, I've just received the ICs.
But, until now, I just removed the 10k resistors (disabling the feature which reduce current to the stepper motors when the motors were idle) and the speed was raised from 750mmpm to 1000mmpm without loosing steps. I'm using 3Nm steppers with 3A/ph, powered at 24v and TR16x4 screws.

I've made some testing at 1200-1300mmpm but some steps are still loosed.
I'll do all remaining mod's steps in the next days...

The hissing noise was also reduced, not completely, but still reduced.

So, you can test it just removing these 10k resistors. If no difference will occur just undo.

It worked for me.

Thanks

Looking at my board.. I don't have a 10k near pin 3.. I have a 4.7k that looks like the one everyone is removing and placing somewhere else on the board. Is that the correct resistor?

Also, I would just rather by-pass the funky opto isolator stuff instead of trying to add in another 7414.. I don't think there is a need to add another one..