[othar]

So going on your last suggestion which seemed very likely:


-aperture ring is set to the narrowest setting (f22? f32?) and the aperture is fully closed (or vis-a-vis: f3.5 and aperture fully open) -> correct assembly with full functionality

which when looking at the mechanism seems to be the most logical. I manually set the position internally to to the smallest opening (f22) and then made sure the aperture ring was on F22. This allowed me to reassemble it. Unfortunately it seems like the first few stops below F22 don't do anything to open the aperture, then probably at around F8 it starts to open up then around 5.6 or a half stop in between it stops getting bigger and never seems to open to the same amount as when I manually move the mechanism labelled Aperture Control in my photo to the most open position.

It completely makes sense this 'should' work.

The only explanation I can think of is, that the spring that closes the aperture mechanism needs some prestress.
Try to rotate the final ring one hole further after inserting the pin into the aperture controll (but don't force it, you don't want to break the spring if this is the wrong approach)