thank you all.
the amateurish repair was mine, as I already tried to remove the lever and see what happened. but I couldn't because it was too stiff.
I bought a pair of pliers and managed to open it and you can see what the problem was...it was sure dropped and aperture is oval, so it can't come back freely. anyway I removed a little of dust and it was working.
BUT while reassembling it I screwed somewhere with the speed dial and now everything is jammed and nothing work. I blame myself for believing I could fix it...
anyway the camera costed me 10€ (sold the lens it came with) and I can afford a CLA, hoping they can fix my disaster.
as for the stiffness, the peg can move freely but with some effort. it has no jams or clicks, same stiffness all over. probably with some lubrication it will be back to normal.