Thanks Dan for the reply. Well I had already taken everything apart and cleaned all the seals, and re-installed the MS end of the column in a new ferrule, because I thought there might be a leak because I thought the rough pump was a bit loud for too long. Although I didn't conduct the deadspin test as you describe it, I noticed while handling the turbo pump that the blades seemed to move freely. Upon reassembly, as well as trying another old pump we had for spare, I don't think it is the rough pump. It is pumping quietly now, so I do not think I have a leak. I could redo the deadspin test to make sure, but I'm now thinking it is the controller. Do you think we can find one or are these not made anymore? I haven't looked in the electronics side yet to see what part it is to look up.