Strange driver behaviour

Firstly, I have to apologise as I'm reposting this from the 'reprappers' forum as my post has gone a bit dead.

I'm running a Ramps 1.4, controlling with Pronterface and have tried with both Sprinter and Marlin.

I have a Pololu driver, controlling the x-axis, which works absolutely fine when running the Ramps test file, but when attempting to control it via Pronterface, the stepper motor just makes a high pitched tone, and the stepper motor turns on (I can't move it with my hand), but won't move itself. I've moved the driver around the Ramps and the same issue arises.

I have mechanical endstops, I've checked them and are fine and also checked the digital endstops also - again fine. So i'm absolutely fresh out of ideas and would appreciate some input. This the last thing before I can print.

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This the last thing before I can print.

What SPEED to you have set in Pronterface.

If you try to move too fast then nothing will happen.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

You can reduce the value in XY: box in Pronterface to reduce the speed.

the XY speed is at the default setting of 3000 mm/min. However, in this case the Y axis is fine, moves as expected, its the X-axis that just locks itself...I have switched the drivers around, and the problem follows the driver itself. But I can't understand how something would be wrong with it, if the ramps test-file moves all of the axes properly.

I've tried lowering the speed and no change sadly.

It may well be that either wiring is wrong or x-axis Pololu is no longer working.

I've moved the Pololu around the Ramps board and the issue is repeatable with other motors. Is it possible the Pololu is no longer working, even if the Ramps test file works?

If RAMPS test code is able to move the x-axis motor then the Pololu is Ok.

When you say RAMPS test file works I am assuming it moves x-axis (and all the other motors too).

Can you try without the belt? Could it be a too-hard to move x-axis?

Alternatively, do you get similar result if you connect x-axis ouput to y-axis stepper? (remember to do the change without power).

If the motor rotates with the test program presumably the only difference is it is slower than the normal firmware.

Have you adjusted the current on each of the Pololus? If the X driver was set lower than the others then it would completely explain your findings. I.e. it might be able to move slowly in the test program but not at normal speed.

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[www.hydraraptor.blogspot.com]

Another possibility is that the driver is faulty in that it is doesn't respect the microstep setting and is trying to go faster than it should. Again the test may work if it runs slower. To verify that you would have to notice if it ran at the correct speed in the test, i.e. the same as another driver.

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[www.hydraraptor.blogspot.com]

@misan - yes the same results if I connect the Y-axis motor to the X-axis Pololu. I have also tried it without the belt, still no joy. And when I test with the RAMPS test file, it does move all motors and heats the bed and extruder fine too.

@nophead - I have increased the current, while also reducing the speed on Pronterface, it just clicks a hell of a lot and the belt rattles, but not much movement. Re-ran the test file, and the X and Y are moving at the same speeds! ...seriously what is going on?! I'm starting to think, I may just need to buy a new driver. But it's still perplexing as to why this is happening...

I think you might have make a mistake on configure.h or pins.h. That might explain your findings too. Can you try again with a clean (unconfigured) firmware?

I think it's more a driver issue than a config file problem, as the error is repeatable when I move the actual Pololu to a different socket - but I will try nonetheless. Have gone ahead and ordered another driver anyway now