Thanks for those answering my questions on my odd 5400 motors 5600B control box situation. Now I have it working with LVB Tracker and Nova. But the motors stop tracking after a few minutes. First it seems to track fine, with motors turning as Nova instructs. But after a few minutes of activating and turning motors here and there, the motors don't seem to respond to the Nova software to move any more. I have to shut down Nova (getting a cannot write to file error), reboot the computer (otherwise when I go to Nova I get an error msg that the device is already connected? (but no response)), and restart Nova.? Then the motors will seem to track as Nova directs, but only for a few minutes and then motors stop working again.? I cannot tell if it is a computer problem (IBM T41 laptop, Win XP), or LVB (just got), or what? Any clues?? Thanks for the space. Bennett ko2ok