So, it isn't heat. The stepper driver chips are cool to the touch immediately after powering down, as are the stepper motors.
The problem is not that the hot-end moves up and down as it crosses the bed, that would clearly be firmware / settings causing problems. The problem I am seeing is that if I jog the hot end, say, 50mm on the Y axis four times, the fourth time it returns to the center of the bed, the hot end will have dropped a millimeter lower. It's like the motors can't counter the gravitational force, but they feel like they have plenty of torque if I attempt to move the carriages without disengaging the motors.
Still not sure what to check next. Could be the belts skipping, or maybe I misjudged the amount of torque I am getting and need to turn up the voltage.
The problem is not that the hot-end moves up and down as it crosses the bed, that would clearly be firmware / settings causing problems. The problem I am seeing is that if I jog the hot end, say, 50mm on the Y axis four times, the fourth time it returns to the center of the bed, the hot end will have dropped a millimeter lower. It's like the motors can't counter the gravitational force, but they feel like they have plenty of torque if I attempt to move the carriages without disengaging the motors.
Still not sure what to check next. Could be the belts skipping, or maybe I misjudged the amount of torque I am getting and need to turn up the voltage.