I have an old cnc wood router I built with ideas from this site several years ago. It worked ok till now. I run master5(from art before mach); using stepperworld's sp-3 and little japan servo steppers. Was quite cheap at the time but ok for light work. Now when I run a program Z will go positive for clearence but will not go negative into the work. The program waits for Z- and the DRO shows its moving but it doesn't. While a g-code program is running there is no holding torque on the Z motor. I swapped Z motor for Y still has no torque on Z.(I can spin the motor with my fingers). Here's the kicker, the Z axis will jog up or down with holding torque on the motor as long as a g-code isn't running or in manual! I am stumped. Any help? Thanks Paul.