Fanuc 6M overtravel won't clear.

Folks--

What follows is a question regarding a limit switch problem on a Fanuc
6M.

Background:
I have worked on many different types of film processing equipment in my
job at a major Connecticut newspaper. Several years ago I added CNC
controls to a ShopTask mill/drill that uses Dan Mauch stepper drives,
and EMC.

Question:
My father recently purchased a Shizouka mill with Fanuc
6M control. He is chasing a problem with the -X, and -Y overtravel
switches/electronics. He has been unable to get the machine to clear
the overtravel errors. The switches are OK as tested with a
multimeter. He checked the + side of X, and Y to ground with a
multimeter, and there is 24VDC at the switches, there is no voltage on
the - side of X and Y. He has gone through all the fuses, and all are
verified good with a resistance check. He has also verified wiring
continuity is OK. Apparently the machine has a board in it with two
rows of relays. There are two empty sockets on the board. He has moved
relays into the empty sockets to prove if the missing relays are related
to the problem, but the initial symptoms have not changed. Is there
anyone on the list with experience with Fanuc controls that have seen
similar symptoms? Is there something common to the + axis on X, and Y
that he should be checking? I am thinking maybe an E-stop, or interlock
board...

I have been trying to help him over the phone, but have not had a whole
lot of success because I have only seen the control in photos, and my
only CNC experience is with the old DeskNC, and EMC...

You can look at my setup at: http://www.stevesys.no-ip.org/ There is a
photo of my setup on my Talon page, and a couple more on the spur and
christmas ornaments pages.

I am grateful in advance for any assistance anyone can provide.

--
Craig Stevens <craig.stevens@...>