Motors moving so fast with Mach2 - stuck Z axis up too far

A bad thing happened just now... My Bridgeport with dead Boss 6
control) mill just retracted the quill up past the upper limit
switch and is stuck. I am in the process of trying to retrofit it
with a new controller when I got the motors going so fast with the
new Mach2 that it retracted too far before I could stop it.
Unfortunately I am still in the process of getting the limit
switches to work. All I can say is @#%^%$@&$^!

I am afraid the ball and quill extension mechanism may be ruined.
Does anyone have any advice as to how to ease it back into working
order or shall I call my local repair dealer for a new mechanism...

thanks
Keith Clark