Originally posted by Not a Number On my Super-Multi-Coated Takumar 50mm f/4 macro the pin stays in when set to "man". If you switch it to "auto" the pin pops out and it locks in "auto" until you depress the pin. When set to "auto" the pin pops out when you release it after pressing it in (spring loaded).
Then my two have either stuck with age or someone has glued them.
Edit even though the pin isvery fine I suspect it will extend too far for a feeler gauge to get under it but here is hoping.
And I wonder if my ones are stuck because someone has forced them and bent them a bit. (It may be the way to go)
EDIT again. If the screw slot happens to be in the exact radial from the centre position then it could trap the pin just like a missing screw.