Fujinon 60mm f/2.4 aperture ring problem

Shortly after I bought this lens used, it began to misbehave. At wide apertures 2.4 or 2.8 it would switch to "P" i.e. the lens behaved like it was on "A".

I found some references to this type of failure on Fuji-X-forum and that I should send it to Fuji for repair. It is an electronic or mechanical issue, not software issue, so I told myself: what the hell, I am quite experienced with mechanical camera body repairs and MF lenses CLA, so I jumped right on it.

The bayonet ring goes off easily, but there is this flex ribbon circuit. Best is to disconnect it - there is a latch on the oposite side than where the ribbon goes out.





Under the bayonet, there is a large metal C ring, probably just a spacer.



Be careful because in my sample there were also 2 small spacers. I really don't know why would anyone mount the bayonet spaced more one one side than on the other side... but I left them in there. (pictured below with one of the bayonet screws for scale, they are also in the picture above)



The second ring with the red-dot and serial number is held in place by 2 tiny screws.

Then comes the difficult part - the aperture ring itself.

There is a detent ball on a spring, be careful that you don't lose it. Work over a developing tray or something similar.

The aperture ring can be taken off in position at f22 or "A" - there is a cut out for the brushes. They can be gently bent back if distorted while removing the aperture ring (don't ask how I know it)



After this step I immediately understood why the aperture setting 2.4 and 2.8 wouldn't work. Take a look at the following picture:



The conductive "paths" of the aperture setting encoder are just a sticker, and it started to peel off and got out of the trace of the brushes. Simply on the 2 mentioned settings the sticker with the "paths" was no longer in the correct position where the brushes would contact it. This is what we are paying for. Very cheaply made internals IMHO.

I sticked it back in the correct place, pushed it really hard in hope that it will stay in place for a while. If I need to do it again, I will use some epoxy.

Getting the aperture ring back on is a whole new puzzle. The problem is the ball on a spring. I solved it by using a piece of aluminium can. Keep the can piece in place, don't move it or the ball wil fall off of the spring and the aperture ring will damage the spring (don't ask how I know this). As the aperture ring slides on, it pushes the spring and ball into the hole. There is just enough clearance for the aluminum can piece. Anything thicker wouldn't fit.





The rest is just "follow the steps in reverse order"

I hope this helps someone. I am sure I am not the only one with this problem.

PS: After the problem has returned, I reopenned the lens, glued the encoder flex circuit with a tiny amount of transparent epoxy, and then the lens has been OK for years.

Originally posted in the Fuji-X-forum on 2015-07-31