Hi everyone and thanks again so much for all the leads. I looked and looked online but could not find a diagram showing the tensioner on our particular machine. A question about it and description of our tensioner posted on a collectors forum did however elicit a response from the administrator. He posted a picture of the exact tensioner we have. It seems our machine was one of a very early batch of 201K's manufactured in Scotland that used this un-numbered tensioner only a short while before they began using one with the numbered dial. Evidently the user manuals didn't show the one we have because they only used it very early. I treated it like an unfamiliar die and tried several assembly approaches, finally finding how it goes back together (photos before disassembly for me here on out). Happy dance!! Don