Y Stepper Motor has suddenly gone weak

The past few days I’ve been fighting with some issues with cutting accuracy. After a few carves I realized it was happening on the right side of the machine (Y2). When the machine is running I can very easily push the Y axis on the right side, the left side seems to hold tight like it should. I’ve done the following:

  1. Made sure $1 = 255
  2. Belts are tight
  3. Made sure wiring on the shield and connector were tight
  4. Swapped the Y2 motor for Y1, same weakness issue
  5. Swapped Y2 motor for X, same weakness issue
  6. Tugged all the connection points for Y2, no change
  7. Changed voltage on Y potentiometer, no change
  8. Tried toggling DIP 4 on Y, no change
  9. No noticeable difference betwen Y1 and Y2 wiring
  10. Multimeter seems to think that the wiring is fine. Resistances look good and there doesn’t appear to be a short
  11. Pully seems to be attached to the motor shaft just fine

At this point swapping the connections to the motors should have ruled out just about everything except the wiring and the motor itself. I’ll bust out my multimeter here in a few just to make absolutely sure there’s not an issue with the cable (which was installed only days ago) Is there anything else I should be checking before I start looking at a broken motor?

UPDATE: I just ran the multimeter. I can’t find any noticeable difference between Y1 and Y2 wiring.

UPDATE 2: Added results from multimeter, next step to take apart motor housing and see if I can spot damage.


What are the resistance measured for each wire pair for both Y1 and Y2? (Measure X and Z too just to have more data)
Also try to verify that the motor shaft is intact and that the press-on pulley isn’t slipping on the shaft. Both could happen.

Does the motor move with the belt removed?

Y1 pairs were ~2.3 and Y2 pairs were ~2.8. That seems pretty normal considering the Y2 cables are longer. The motor shaft seems to be perfectly fine from what I can see. It doesn’t appear that the pully is slipping at all. When it’s running it almost just looks like it’s not getting anywhere near the amount of current it needs. I might pull the motor off and crack it open to see if I can spot any damage in the housing.