Well, if the aperture blades are sticky ... that would prevent movement. There is a spring that returns the aperture back to its tightest position. It also could be SPRUNG, so to speak. Usually you will see the aperture blades visibly widen when you put on the rear lens cap (provided it has the blade actuator in it).
When I put on the rear lens cap and tighten it, the aperture blades goes visibly widen. But they stay that way, when I remove the lens cap, so there is no /is not enough force from the spring to return them back to smallest aperture.
Originally Posted by DonSchap
I hope its enough to clean the iris blades to get it functioning again. However,
if the spring is damaged, where can I buy a new one?
/garda from Sweden
Your picture shows the Aperture Lever in the open position. It would normally be in the closed position.
Get one of your other lenses and move the lever to and fro to see how it feels against the resistance of the spring.
The comparison between the two should give you a good idea of whether the spring is the problem or not.
I have moved the lever back and forth on my other two lenses to compare with my minolta lens. It seems to be the spring on the minolta that is the problem.
Where do you think I can find such spring?
Is it the spring with number 2550-1420-01 that is seen on this url: http://www.pbase.com/pganzel/image/54100026 ?
That's the one. You need to see what's gone wrong with it.
It's easy to get at on the back of the lens mount.
Just watch out that the Drive Pin and ground spring (tiny) don't get lost.
Thank you for your information!
Originally Posted by Peekayoh
I will borrow some tools from a friend. One thing to be clarified: To get to this spring and to remove the iris (blades to be cleaned), is it easiest that I open the lens just from one side?
It seems easiest to open the lens from the back (the side towards the camera housing)?
(I will follow this tutorial, by the way: http://www.pbase.com/pganzel/disasse...xxum_50mm_lens )
I'm afraid you may have to do both.
Open the back first and fix the problem with the spring.
If that solves it you're good to go. If not, the iris assembly comes out the front door.
I have opened the lens from the back. A tiny small spring was found loose. It is probably the ground spring, that was mentioned by Peekayoh further back in this thread. See pictures:
Attachment 50883 Attachment 50882
On the second picture, the spring for minimizing the iris is fully functional (2550-1420-01), so I will open the lens from front-side to try cleaning the iris-blades. I think the loose spring has part number 2550-1424-01, as seen on this picture: http://www.pbase.com/pganzel/image/54100004 By inspection of that picture, I found where the ground spring shall be placed.
Any feedback on the operation is welcomed.
I have successfully cleaned the irisblades and now the lens is fully functional! :)
I lost the ground spring, but replaced with a bit of copper wire, as suggested in the comments of the tutorial I have previously linked to. Thanks to this thread and the tutorial, my lens is now working. Great.
Well done, garda. :) Now post some pics.