Hopefully Im posting this in the right spot. I have a prusa i3 controlled by ramps 1.4 and marlin, 20a power supply, heated bed and the 12864 smart LCD w/card reader, etc.
The issue im having is that when jogging the z axis after a few secs of steady movement it will move maybe 10-15mm then stop for a sec, then move another 10-15mm and stop repeatedly until it reaches in destination. It also appears to throw off the DRO some. Its a dual stepper running off a single driver, both are moving in unison, no twisting, no strange noises or "missed step sounds". No idea where to even start. I believe its the A series driver (its about 6 years old). Im considering upgrading to something newer but want to make sure this isnt a bigger issue before i start ordering new parts.
Brian