3 year old Pro started having intermittent trouble with the X axis stuttering during homing and jogging. Seemed to get through cuts okay. The other day it became a constant.
Played with belt tension, which lessened the severity if loose rather than tight, but still stuttered every time it homed. Checked servo plugs but no sign of damage or lose wires. Set screws are tight.
Bought new belts and no change.
Swapped X & Z cable behind the HDZ and no change.
Swapped X & Y motors and no change.
While debugging, realized I could stop the carriage with my hand, using very little effort, while the X axis is homing. Swapped the X & Y motors again and could easily stop both. Measured it to take 9 lbs of force to stop it.
Have you swapped the connectors at the point they connect to the controller board? If not, that would indicate pretty conclusively if it’s a wiring or board problem.
Removed the HZD mounting plate and found the tie plate to the bearings had 12 of 16 screws loose, allowing the unit to twist slightly around the Y axis when encountering a load in X.
Also helped a lot when I sprayed the X bearing rails with a light coating of Boeshield T-9. Got to make that a PM.
Using a light oil regularly for the linear bearings is going to help flush any debris that they may collect. I see that your Boeshield T-9 is advertised to dry to a clean, waxy, waterproof film. Great for bicycle chains,