Help - Machine Down

Greetings,

Went to machine some parts on my milling machine. Four axis, XYZ and A(rotary table). Vertical mill.

Clicked on Home All, and as the Z-axis was homing I clicked on MDI to see if G55 was active or not.

Then all motion stopped.

Next, I click on Home All and the Z-axis is going the wrong way! It is headed for the table instead of going up and homing.

The only files I can see that were modified were emc.var and emc.var.bak.

I copied these files from an old configuration and pasted them into the current configuration.

Powered the computer completely off and restarted.

The Z-axis is still going the wrong way.

Please let me know what to fix as I need to make parts.

Cheers,

Dave

Greetings,

Had a vision. Better check if X and Y home properly.

So, I homed X and Y manually. All went well.

Then I removed the cover to the limit switches for Z.

Next I homed Z with my finger on the Red Button, just in case.

Surprise!!! Z homed properly.

Despite all is working, what happened originally?

Cheers,

Dave

Just venturing a guess, sticky switch, bad contact, bad wire, or some other problem relating to the Z axis home switch signal.