M2 Not homing correctly y axis

[grant1842]

Hello all.
My name is Grant.
I am looking at a M2 for a friend.
If the bed is half way or all the way forward and you home the y axis it only moves a couple of inches back and stops.
You have to home several times to get it to go all the back and hit the limit switch.

If i home the y axis and hit the limit switch it will stop it.

I did flash the firm ware again and same problem.

I did send a G28 command and same behavior .

Thanks for any help.

[grant1842]

Here is a video of the problem.
https://www.youtube.com/watch?v=jbNy-HzAmeM
Has anyone seen this before.

Thanks

[ednisley]

it only moves a couple of inches back and stops

It's a mechanical problem: most likely, the linear bearing track is full of dust and congealed lube.

Remove the belt, slide the platform all the way back, clean the exposed track [0] with denatured alcohol [1], slide the platform all the way front, clean the rest of the track, and repeat until the platform slides easily / smoothly over the entire range.

Add some light oil along the grooves in the track, feel how nicely it moves, reinstall & tension the belt, and you're good to go.

If the platform doesn't slide easily and smoothly by hand after you're done cleaning, figure out what's holding it back and fix that problem, too.

[0] Dust on the top doesn't matter. Clean the grooves on the sides of the metal bar where the balls roll.

[1] Which may be unavailable, because COVID-19. You can use a light oil like 3-in-1 as a "solvent" or, if you promise to wipe the track very very clean when you're done, a penetrating oil like WD-40 / PB Blaster will work. Don't spray the bearing to avoid hosing down everything in the room: spray into a rag to wet it, then wipe the solvent along the track with the rag.

[grant1842]

Thanks for your help.

I finally found the problem.

There was a intermittent problem in the wiring that goes from the y motor to the PCB.

Thought I would post the fix in case some one in the future has a simalar issue.

[ednisley]

intermittent problem in the wiring

Now, that's pretty far down on the list of things to check! [grin]

Thanks for following up, because somebody else will definitely benefit from your experience …