New 750 machine less than 2 weeks ago. I’ve run 6 or so projects without problem (other than my own stupid mistakes). Today I was running a piece of maple with a V-bit and I killed it when it started making heavy groaning noises. Turns out the maple which I had jointed and planed last night was now bowed in the middle. Probably because I put it on a heater to dry paint faster. Another dumb mistake.
Now I have Y chatter and get a homing error even though it hits the limit switch I have cleaned the hell out of all the pulleys, the rail, and the belts. I don’t have a fish scale but the belts feel equal and twang when I snap them. I did find 2 loose pulleys and tightened them up. There are no grub bolts in the drive wheels on the stepper motors, as in the wheels are bonded to the shafts apparently by magic.
When I move the rails in the Y direction by hand (slowly) it feels smooth 9 times out of 10 then once in awhile it feels like I push it over an obstacle but there are no obstacles, not even dust. And yes I have been running the dust collection with the boot.
I don’t know what else to look at. Help…
Fixed!! 
Very slightly unplugged Y-1 motor. I had read to check that in another thread but ignored it because I thought both motors were running but apparently I was wrong
1 Like
Did that solve your problem?
I am having the same.