X axis will not home micromill

[tuce]

If anyone could give me some direction it would be much appreciated. I have one problem and a couple of questions.

I finally got my micromill to communicate with the software after making a new serial cable 9 pin to 9 pin from the PC to the controller, Thanks guys for directing me where to find the wiring diagram. viewtopic.php?t=544.

Can I leave this cable for permanent use of the machine or is it just for testing?

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My next question is how can I tell what Model Micromill do I have, Micromill, Micromill NS or Micromill 2000? There is no tag with model number or serial number on the unit. When I load the software it asks to enter the unit / model. I am running VR CNC MILLING 2.28.

And now the issue is with the X axis. At first the X axis was stuck and would not move at all. I found the pin that holds the gibb in place came loose and wedged the gibb and tightening up X axis. After fixing this problem and the X axis moved freely I tried to home X, Y, and Z axis. Y and Z axis work great goes to home hits the limit switch and backs off just a bit releasing the limit switch. But when I try the X axis the motor moves X axis to home hits the limit switch and stops but the motor keeps on growling, motor is still running. I tried a couple of things and know the limit switch is good through an ohm meter and some testing. The set screw is making contact with the limit switch and verified this with an ohm meter after securing all power to the micromill. I tried going to home several time and the direction of the X axis is not consistent; sometimes it wants to go the opposite direction from home. I also had the same result when I jogged the X axis by means of the computer keyboard. I found when I jogged X axis with the X key and it moved the X axis just fine, but when hitting the same X Key on the keyboard a second time the X axis went in the opposite direction.

At this point the only issue is with the X axis and was wondering because the X axis was frozen up at the beginning could have this damaged the stepper motor causing these problems?

[Martin]

Your machine has a Denstep top card fitted & will not communicate if you select a NS machine.

It sounds like you may have a broken wire going to the X axis stepper motor.

Check the resistance of both coils. Some of the stepper motors had a small pcb which the wires soldered on to & I have seen these detach at this point.

The other thing you could try is to plug the X int to the Y axis drive & use the secret home button to enable you to determine if it's the motor or drive.

[tuce]

Martin

Thanks for the info; what you suggested made a lot of sense so I went directly to the motor and ohm it out. I found a leg open and after investing further sure enough found the break in the white wire as it goes into the motor housing.

Thanks for the reply

[tuce]

Martin,

Thanks again, that fixed all the problems. I found 2 of the 8 wires broken in the insulation. I can see over time as the motor moves with the X axis working the wires back and forth eventually breaking the wires.