very good and complete manual , it is in english and german is perfect for repair.
Text excerpt from page 19 (click to view)
Installation of Rotation Stopper (Semi)
Step 1 Fit the tab on rotation stopper (semi) into the opening on spindle base. (Be careful as the size of tab differs).
Step 2 Lower down the rotation stopper (semi) and fit the trapezoidal tooth between bottom spindle and relay gear A.
Step 11 Press down the bottom hook with a fine-tip minus screwdriver. Step 12 Hold the axis part of the bottom hook and pull it out.
Step 13 Turn the bottom spindle in the direction of arrow until it hits against the stopper. Step 14 Insert a fine-tip minus screwdriver between the bottom spindle and UP/DOWN base and slightly raise the bottom spindle for it to go over the stopper. Then turn the bottom spindle and remove it.
Step 3 Insert the rotation stopper (semi) and ensure that the tabs are engaged.
Step 15 Rotate the UP/DOWN base 90Â°. The spread the leg portion of the rotation stopper and remove the UP/DOWN base. 19