This is a strange one, I have looked all over forums and can't seem to find the answer. not sure if my case is unique or not. I am a newbie to the CNC router world. however I have been 3d printing for years and laser cutting for a few years. so not fully new to the concept.

I recently bought a CNCEST 6090GZ, and a copy of Mach 3. I have cut several jobs already and everything worked as it should, thanks to all the help that is out there on the web. I hoping you can help me with this one.

On the last job I was cutting, I set the spindle speed a little too low, and I went to increase the speed using the + button. in past jobs it increased the spindle by 10% and all was good. This last time the spindle increased to Maximum speed, and tried to back it down using the - button. the speed did not change. I let the job complete and started to experiment with spindle speed.

here is what is going on. I set the spindle speed and started the spindle, it would go to the speed I set. then I use the either the + or - and it go to the maximum speed. So I then typed in a speed and it would stay on maximum. As I experimented I typed in lower and lower speeds. this is where I learned that either Mach 3 or the controller would multiply the input speed by 100. so if I wanted 15000 RPM I would type 150. This is only after the initial speed is set and the spindle turned on.

If I turn the spindle off, set a speed (say 15000) it will come up to that speed.

I tried to reset the VFD controller and reload the Mach3 XML files. but doesn't seem to fix the issue.

Anyone have any Idea what might be causing this?

Mach3
CNCEST 6090GZ USB
110V 2200W Water Cooled Spindle