Longmill MK2 going haywire

Hi there my MK2 (48x30) just started doing something strange. Finished a couple of projects a couple of days ago, no issues. Loaded a new gcode file, zero’d my machine, then ran an out line test. The project sized was only 8"x16" and my piece was positioned close to front left of machine. Outline run started fine, then the machine went way off to the right of the work area, only in the x direction. It looked like it was outlining way over there, and was making some grinding noises. When it stopped, still sitting far right, my X and Y location co-ordinates read “0, 0” !?!?. I just installed newest version of gsender (1.4.10) tried again and same crazy result. Does anyone have any thoughts on this? Tried another g-code file and same result. Machine ends up off to the right of the workspace, reading “0, 0”.

Could it be that there is some sort of obstruction and the x stepper is dropping steps (grinding noises)?
If that happens, the software doesn’t know what has happened and the new physical 0/0 location has shifted.

Which read 0,0 - the workspace coordinates (blue numbers) or machine coordinates (grey numbers)?

It’s possible your post processor included a G28 command - you can check the first ~15 lines of your gcode. If it’s there, your post processor is configured incorrectly. You can search the forums for ways to fix it for your specific design software since it comes up frequently.

I don’t think there are any obstructions, have tried jogging the machine around the workspace - don’t seem to be problems. I did notice that when I try to jog in “Rapid” movement, the machine stalls and grinds from time to time, mostly in just the x travel. I installed the new anti-backlash nuts a while ago and the machine seemed fine. Could the x nut need adjusting? I thought they were pretty much self adjusting?

Unfortunately I can’t comment on the anti backlash nut but I would reduce my maximum x speed and possibly reduce x acceleration and see if that fixes things.

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So, dumb question. What is the difference between the two sets of coordinates? I guess I have never paid attention to the gray numbers! And perhaps another dumb question - how do I view the g-code? Sorry, obviously still a newbie after 2 years.