Hello all, question for you with a little background.  I have a shizuoka mill with ametek servo motors and 2 old logitrol driver systems with gecko drives. Running mach 2. I'm ready to upgrade to 3 if I know the machine is going to work. Problem I'm having is when I move by keyboard with any axis it advances smooth then acts like something grabs and will stop feeding smoothly and bumps for a few to 30 seconds then goes back smooth for an inch or 2 then grabs again. When it does this another axis will also bump around out of place but won't change position on screen The axis' keep advancing normally on the screen and can end up 15 or 20 inches off on the z axis which isn't even possible.

When the machine is off all the axis' move smoothly.Would you think its bad motors, something feeding through old wiring, drivers, anything? When I run a part some of it looks like its trying but then it drives too deep or loses position like it does manually giving the other axis a problem then just keeps going. I'd sure like your thoughts, I appreciate it. Thanks

Well after monkeying around with it more today I think my servos may be underpowered. when I took the drive belt off the z axis and commanded it to move it ran perfectly till I put a bit of load with my hand on it. It would cause it to bind up and pulse or bump. I imagine the other axis are the same, when I could push against the table in the same direction of travel it seemed to smooth out. I had replaced one of the power supplies but I don't know if that could be the problem or tired motors or would a person need to tune the drivers? Thanks in advance for any advice!