Re: Missing steps with lower feed
I would strongly recommend contacting Gecko drive customer support.
Swap drivers between X and Y axis.
Swap signals on the break out or whatever is doing the motion control. (providing the step/direction signals)
Swap motors.
If you can't or they can't help you, beg, borrow, steal, or :shudder: buy an o-scope and look at the signals going into and out of the driver. E.g. the step and direction and the motor phases out. See if anything looks wrong... not getting a full swing from logic 0 to 1? Noise? Drive cutting out? It can be really hard to see an intermittent issue (which it sounds like this is)
James hosts the single best wiki page about steppers for CNC hobbyists on the net:
http://www.piclist.com/techref/io/steppers.htm Disagree? Tell him what's missing! ,o)