stepper motors jumping and making a clicking sound

Hi everyone

I have recently finished assembling the persa medal and have wired in all the electronics, but when it came to running the motors for the first time (using ponterface) they would run for a fine for 20mm or so. Then they would run in really erratically and not travel the same distance each time. They also make a clicking sound (sounds like the hamster inside the motors in having a panic attack)...

I've checked all the runners are parallel and greased them, it all runs smoothly when pushed by hand so its definitely not friction which is stopping the motors from moving, also checked all the electronics and all the belts and all seems fine. So that just leaves software doesnt it?? :-/

Anyone with any idea as to what it might be would be appreciated

Thx in advance

Pololu drivers might be turned down too low, or software/firmware might be pushing too fast for the steppers to follow. Try turning up the current on the drivers, and turning down the max speed in the firmware. Also make sure your steps per mm is correct.

...Or Pololus are turned up too high, and the thermal protection is kicking in. Either way, you need to start with the current set low (using the variable POT on the pololu), and ramp it up until you hit the right spot (don't go beyond half way though).

You may also consider (do it!) installing heat sinks, and a cooling fan.

Do the steppers turn correctly without the belt?

I had the same problem, i connected the stepper loops incorrectly to the driver. They did turn but very erratic and made a lot of noise.

see also the last post of this thread:
[forums.reprap.org]

evilb Wrote:
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> Do the steppers turn correctly without the belt?

This +1

Check your connections. I had a similar problem when 1 wire to the motor worked loose at the crimp terminal. The connections looked alright by eye, but the wire was just sitting in there loose.