We got our BMC 20 Max II machine working after having the memory and batteries upgraded. It worked for awhile and then went down and now it seems to work but the axis movement is off. The DROs say the machine has moved 7 inches in Y but actually it moved 14 inches and the Z axis indicates 24 inches of movement when it actually moved about 12 inches. It looks like the leadscrew mapping data has been damaged. We can get the machine to reboot using enter 999 enter but what is the sequence to reestablish the lead screw mapping default.

Thanks

Here's a link to a similar thread.
http://www.cnczone.com/forums/showthread.php?t=44740&highlight=bmc20+642

I appreciate the link. I have already employed Martin CNC to do the battery upgrade. It looks like our machine is calibrating fine but it is not moving correctly despite reloading the leadscrew mapping data. Must be another board going bad...

Pull the boards and clean the edge connectors.
Have you swapped the servo amps for the Y & Z over? If it's a Yaskawa linear rail machine, there is a 1:1 ratio for the X & Y and a 2:1 ratio for the Z.

Just for the purpose of information, when I had the battery issue on the memory board of my 91 BMC20, I sourced the I/C from the manufacturer and replaced them, cost me 80 bucks. The I/C's on the board have batteries with a 5 year life span, the standard by the manufacturer was 10 years at the time, the rep said he never understood why they were spec'd out for only 5 years. I'll get more detailed in the future, but, if you do an internet search on the part number on the I/C's you'l find a cross-reference, then just order them from Digi-key.