I have an 2005 machine with servo's. Check your soft limits. I keep mine off & make sure I'm not going to be anywhere close to the hard limits. At 300ipm, you have to be at the top end of the max stepper rpm. At max rpm, your steppers don't have much torque.
Any misalignment of the screw & it will bind enough to make the stepper loose steps &/or stop. Check the screw to see if it turns freely at both ends of it's travel. Also check "X" & "Y" tram. There is a post on the zone somewhere on how to check the tram.
