erik fiss | galleries | Yashica Electro 35 Repair Manual

On reassembly, the tab on the diaphragm setting ring must pass through the fork in the diaphragm control ring. Turn both the diaphragm setting ring and the diaphragm control ring to one of their two extreme positions -- the smallest aperture or the largest aperture. To set the diaphragm control ring to the largest aperture, turn its forked tab all the way clockwise.