I'm just getting my prusa put together w/ ramps 1.4 and sprinter. When I home the x,y,z axis it gets to the opto endstops, does it's back and forth movement when triggered, then the stepper motors start making a high pitched buzzing sound and sometimes won't move in the direction away from the endstop. Has anyone had this problem before?

What happens when you manually home each axis one at a time?

It sounds a bit like your opto end stops aren't happy with the target (optical flag) that they are seeing.

When I home individual axis the x will sometimes do a twitching stepper thing after it encounters the endstop, and the y will make a high pitched buzzing sound when it gets to its endstop. Z seems fine.

The flags I'm using are 3d printed pieces, the switches are optos from ebay. It seems like when it homes and does it back and forth movement after it hits the endstop it will set into a position where the led on the opto will be half lit/dim.

Does pronterface show anything on the screen when a endstop is triggered?



Home position-

Pronterface does not automatically show anything when an endstop is triggered. The LCD display (if you have one) can show endstops.

If you type M119 into the pronterface send window and hit send, you will get endstop status back from the printer.

Normally on an end stop, it hit it, it stops. There is no servo / motion after it hits. The only exception seems to be when it gets multiple hits. Then it moves back and tries again. I don't run optical end stops (don't like them ...) so I'm not sure what they do on a noisy hit.

Did you tune the current going to your stepper motors? Are they getting hot?

I have this same problem the only way I ave solved it in the passed was downloading a Fresh copy of Marlin and then only changing precisely what I needed so try a Default copy and see it it occurs...

Seven years in a coma ?

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"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)