I am still using a BD FACSCalibur bought in 2001. It still works fine except for one problem. Only when the tube support arm is to one side, the sheath fluid drips from the droplet containment sleeve (BD manual nomenclature). The fluid is not coming from the inner sample injection tube, which works fine. It is coming from the outer tube (I confirmed this with the outer tube removed. It comes from the top that should be aspirating.) The instrument analyzes just fine at all 3 sample speeds. I do not think there is a clog in the waste line, but maybe there is somewhere where I can't see it. There are no leaks anywhere or sample pressure problems. The bottom line is that when the arm is to the side, the injection tube drips if there is no plastic sample tube, and the plastic sample tube fills with sheath fluid if one is in place with the arm to the side. I am wondering if one of those little solenoid-type valves is sticking open or closed. I wish I had a maintenance manual, but I've never seen one available. I can't be the only one that has had this happen, so I hope someone who knows what might be the problem answers this. Thanks in advance.