Hi:
Had a "Z mistake " a few days ago and now it won't home correctly. I'm seeking some ideas on where to start looking for the problem. Here is what happened :
I screwed up the Z offset for a tool and it dug into the work  and made some "ugly noises" before I could hit the E-stop. Now when I try to "Ref all home" the Z starts up and hits the limit switch with the E-stop message. The machine coordinates are say "0" in the Z.  I believe it is hitting the limit switch and backing of just a small amount. The DRO Machine coordinate are working and I can jog the Z normally. As before when "ref all home" is selected the the result is limit switch triggered. I am getting an "abnormal condition" amber light with the message: "Axis is not refed to normal condition" I changed to the diagnostics page and have the following: M1++ is yellow, M1-- is yellow, M1 home is yellow.
Am I correct in making the assumption that due to the "crash" the Z has lost it positioning reference due to excessive load on the spindle? Could it have physically moved the switch out of position? OR is this a software issue? So, the 64 dollar question is how do I fix it and get back running.
As always, your stellar advice is GREATLY appreciated.
Thanks
 Caddy