Hi. I bought a used MB3 VMC and it is running with the exception of a tool changer hang-up. It works fine if I call for tools in pockets 6-22, but it will always hang up and fault out when pocket 4 or pocket 23 comes around to the tool change station. Since it works fine at the other stations, I'm thinking its in the rack that moves the tool mag around, but I'm not so great on electric troubleshooting (programmer you know). Help is greatly appreciated!