<p>Hi all<br /> I hope this is the correct forum/place to ask this question.<br /> I've recently acquired a Pentax S1 with an Auto Takumar 55mm f/2.2 lens. The camera seems just about perfect, but the lens aperture wouldn't stop down with the aperture ring. I dismantled the lens and found there is a broken spring which is the cause of the problem. That's fine and I can workout how I can replace that. The problem is there are also some issues with the aperture blades - some of them were not correctly positioned and started to buckle as the aperture arm on the back of the lens was moved.<br /> Because of the danger of the blades becoming damaged, and because one of them fell out of the front of the lens during disassembly, I've removed all the blades with fine tweezers (and fortunately they are all fine and undamaged). What I can't work out however is how to do the final part of the disassembly to get the the aperture plate and refit the blades. I have the focus helicoid assembly, with the aperture adjust ring still fitted and can't find any obvious screws. There is a set of notches on the back for a ring spanner but I can't get it to turn (and I don't want to exert too much force unless I know it should open).<br>
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<br /> Does anyone have any experience of this lens and if so could advise me ?</p><div></div>