I am trying to set up 3 1638P switches to stack using Active Chassis and Stacking XIMS. I have set up the master with VCID1 and backup with VCID2 and linecard with VCID3 and connected them in single loop. The backup and line card see each other, but the master and backup both think they are master. I have put the XIM interfaces in Active Chassis mode and connected them up. The master's two interfaces show down/down. I have swapped out the XIM and still staying down. Does anyone have any ideas?