I have a lubitel with a broken diaphragm, however I am stuck about how to get to it. The aperture blades have dislodged, and I can see there is a plastic(?) retaining ring from the film side that seems to be glued. I am a bit apprehensive about trying to use solvent there. Has anyone got experience with getting to the aperture blades? The Lubitel seems to be fairly disassembly unfriendly. Once I fix it up I'll give to a digi-friend to try her hand with film. Hopefully another convert.