Thanks for the reply.
When I did step 3 above, I used the wiring from off the printer.
Tried again and the motor and wiring work fine.
I am looking a the main board. 5V supply is good, 15V motor supply is good.
I think I am going to try and look at the DIR and STEP pulses next.
I have an old Velleman K8200 printer. It used to run fine and I had no troubles with the x or y movement. As of today, the x stepper motor just jitters when given a move command.
Here is what I have done to trouble shoot:
Checked the problem with MatterControl (latest) and Repetier (old, but know to work). Both software produce the same problem.
Unhooked the x drive belt from the stepper gear. Problem still persists.
Built a stepper motor / stepper driver tester with an Arduino. Used another stepper and tested all four stepper drivers. They worked perfect. Pulled the x stepper motor off the K8200 and tested. It ran fine with the stepper driver that it used in the printer.
I adjusted the voltage in all the drivers to between 0.55V and 0.6V.
Put everything back in the printer and checked again.
The only thing I can think now is that the mainboard has an issue. I’m going to check what I can on it.
Any thoughts about this?