We have just had the same problem with our 2412, it ended up being an adjustment in the head that has to be made manually. I am not sure what the exact fix was because I was not the one doing the repair but it was an adjusment to the limit switch from what i remember. The machine had just hung in tool change position and the only way to fix it was to hit the emergency stop(dont do because the tool will fall out). Once the adjustment was made we had no further problems with the machine hanging up. Sorry I cant give exact details to the fix but I can tell you that it is a limit switch for the tool change.