Y- limit switch behaving strangely

Hello,

I just booted up my mendel90 for the first time. After checking all the limit switches with M119 and finding them all responsive, I tried to home each axis. All went well for X and Z axes but the Y-axis limit switch took a long time to engage (the stepper was sitting there skipping). Has anyone encountered something like this before? Any Ideas?


Thanks,
Aaron


EDIT: After Fiddling around for a bit I noticed that on the Z and X axes, the motor steps back a little after first engaging the microswitch and the re-engages the switch. The y-axis doesn't appear to step back but when I push it manually (as it is trying to run itself off the end of the rail) the limit is detected... is there a way I can add a few more steps back to the Y-home macro to force this behaviour?

Edited 1 time(s). Last edit at 04/19/2014 09:25PM by afsmith.

Loosen the right bar clamp and side it as far forward as it can go. Do the opposite for the left bar clamp. If it still doesn't work loosen the left bearing mount and slide it back and the right one forward.

The design has 1mm of over travel but the screw hole clearances add up to more than that so the left bearing mount strikes the end before the right one triggers the switch.

The firmware doesn't need any changes. It will back off correctly when the switch is working.

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That was it exactly! Thanks. I love it when it's a quick fix like that.