As the title states, my trusty router has developed a problem with it's Z axis motor loosing steps in the ^UP^ direction only.
This started after I gave mach3 a command to GOTOZ whilst doing some rotary carving on my 4th axis. It was a very stupid command to give, as that drove the cutter all the way into the job and ruined it.
I have the Z zero alinged with the center of my part and I've only just started experimenting with the 4th axis. Lesson learnt.
Seeing that my project was ruined, I decided to complete the run and confirm that the job was going to turn out as I'd liked. This is when all my dramas started.
While running the rest of the code the Z axis started making strange noises and proceeded to drive deeper into the job.
I decided that I must have damaged the axis somehow, so I pulled it apart expecting to find a rough bearing or ball screw, but everything looked fine. I then ran the stepper without it being connected to the ball screw and found that jogging in the down direction the motor runs perfectly, but jogging in the up direction the motor jerks and moans and looses steps. Sometimes it even runs the wrong direction. The DRO appears to cycle as per normal and the soft limits were still working as they should.
I have changed motors and driver boards around and the problem still exists only in the Z axis UP direction. I have checked all my motor tuning settings and every other setting that I can think of and they are all set as they have been for years. So nothing has changed in the program that I can see.
My machine is running Probotix BOB and stepper drives, as well as their motors and power supply.
I've been running X Y & Z on 1/4 steps without a problem, and the rotary axis is running 1/8th stepping.
Could I have a bad BOB or parallel port pin? I have had the computer mother board go bad before and that made me suspect the BOB, but with some help from Probotix I was able to diagnose that the mother board had failed. The current board has been running fine for the last year or so.
Could anyone please help shine some light on the possible cause of my problem as I've run out of ideas?