Posted 31 October 2015 - 05:23 AM
On the right side (feed side) just beside the top of the lens port, there is a small Allen socket and lock ring. Undo the lock ring with a 2 prong driver, just a couple of turns, then use an Allen key (2mm from memory) to turn the inner socket anti-clockwise. That turns a worm gear which slowly undoes the big geared viewfinder lock ring which is directly above the lens port. Undoing that ring reduces pressure on an inner friction disk, making it easier to swing the viewfinder over, or reposition its height. Undo it too much and the viewfinder arm won't keep its position.
Once the friction is right, tighten the the little lock ring around the Allen socket with a 2 prong driver again.