Diaphragm does not close

Hello all,

I bought a canon AE1 (not program) long time ago, and I discover that diaphragm is not closing when i trigger the release button.

My lens (old FD 85mm S.S.C with no release button) is good because it's working on another AE-1. And the battery is good.

I also try to "play" with the diaphragm of the lens when it's unmount. I move the "spindle" (at the opposite side of the red point) and the diaphragm is closing well.

What I do :

I put the aperture ring to f16, I put the shutter speed to bulb. I arm the camera.

I open the backside of the camera with no film to see what's happening through the lens.

When I shoot and stay the button press, I see that the diaphragm is not close.

I suspect the "diaphragm control lever" cf page 2 of this service document on this page because I see the control lever still at the top.

And when the control lever is still at the top, one of the spindle (the spindle that move when I lock/release the lens from the camera) of the lens is also at the top, which prevent the diaphragm to close.

I did a second test :

I put the aperture ring to f16, I put the shutter speed to bulb.

I arm the camera and I open the backside of the camera with no film to see what's happening through the lens.

But this time, I action the "stopped-down lever", I see from the front of the lens that the diaphragm is now close (finally). I release the "stopped-down lever". Then now I shoot and stay the button press, I see that the diaphragm is close and the "diaphragm control lever" is down !

Perfect !

If I shoot again but with no "stopped-down lever", the diagram will not close again.

So, why the diaphragm is not closing ?

I have to tell you that the exposure mesure is not functioning, the needle is always go down, even with a lot of light

Thanks a lot