Printer forgets where it is.

I've been having an intermittent issue with the alignment on my Printer.

Using mattercontrol, i'll start a print, and the printer will go to do its auto levelling, it does this by locating the center of the bed, then the front left, front center, front right, then moved to the center right, center, center left, then back to the rear left, rear center, and rear right. Thats what it should do, and usually does.

However sometimes, it will go to the center of the bed, then instead of going to the front left, it moves only fractionally left, maybe moves the bed slightly to the rear, then lowers thinking its in the front left corner, but its not, its still mostly in the center. It then tries to check the rest of the corners but its totally in the wrong place. It ends up checking what should be the center, on the right, and then hits the right end stop trying to go further right, and of the course the belt slips on the gear and makes a godawful noise.

I generally have to switch it off to stop it going further and potentially damaging itself.

The wierd thing is, if i tell the software to "home" all the axes first, it will usually move to the correct location on x y and z. But not always, it will sometimes move the bed slightly to the rear, but not all the way to hit the end switch. Yet sometimes it does, and still does the messed up z levelling when i start the print.

I'm guessing its some sort of firmware issue where it neglects to accurately check to see if its hit the end stop switches, but since i have an E3D head, and Z levelling, i'm not using the standard firmware, but one here from the forums.

Its a pain, i've been trying to print for the last 2 hours, and havent had it do a successfull calibration yet. Yet yesterday I printed several jobs without a hitch. I've tried closing/reopening mattercontrol. Disconnecting/reconnecting the printer in software. Unplugging/replugging the USB cable, and pulling the power to the printer, and all combinations thereof. AND rebooted my pc!

Suggestions???

 

Which firmware did you install?

 

I dont remember exactly, it is one i got from the forums here.
If memory serves i think it was a firmware you posted actually.

 

This one? https://www.dropbox.com/s/hd6djpsdaaqiumw/Auto_Level_6_10.zip

 

Mike: that looks vaguely familiar. I'll have to check the exact file i downloaded when i get home, but i seem to recall the actual post or firmware being dated around march or april this year, to factor in the auto z levelling.

Ziggy: next time it happens i'll try that. Yesterday I eventually turned everything off, and while off i re-seated the connections from the z axis end switch on the ramps board. After rebooting everything, i was able to print successfully.

Whether it was a loose connector, or just having everything off that fixed it, i dont know.