Some other info that might help....
And probably the most wierd thing: The machine will actually move around as expected, the noises are only really after it's idled for a while. The pitch seems to go down a bit after the rapids, and then it starts making the noises.
- The /ENABLE line is solid-low when commanded to be enabled, and solid-high when not enabled.
- MS1, MS2, and MS3 are all permanently tied high, as my delta mechanism really should only be run with 16x microstepping.
- /SLEEP is tied to /RESET per the Pololu page, and the RAMPS 1.4 schematic.
- Motor power is +12V from a pretty standard switching power supply
- +5V is currently from a second +5V switching supply (was going to be powered from USB, but I didn't realize how much current my opto endstops would pull).. next version will have a +5V reg onboard.
- Stepper motors are pretty standard RobotDigg high-torque NEMA 17's that have worked great in the past on a RAMPS board: [www.robotdigg.com]
- Voltage at the StepStick potentiometer(s) is ~1.1V
- There's not really any torque or anythign on the motors while they're making the periodic weird noises.
- The stepper motors and StepSticks have all been tested "good", I've used them for quite a while before putting them in the new board.
And probably the most wierd thing: The machine will actually move around as expected, the noises are only really after it's idled for a while. The pitch seems to go down a bit after the rapids, and then it starts making the noises.