Bernina KL117 upper thread tensioner assembly.

Video on special request, shows disassembly and assembly of the upper thread tensioner of my vintage Bernina KL117 sewing machine.
Attention:
there are different models of thread tensioners on the Class 117!
Some have no middle-disc (the 2nd last part I take out) to tension two threads, some have no "bell" (the first part I take off is just a nut, not a "bell") and others have no tension-indicator (which must be cared of, when reassemble it all).

[@malirocu]

Thanks a lot for your help. Your video has been very helpful to mo. Thanks again.