Auto/manual switch stuck on Takumar 105

My Takumar 105 super multi coated has a stuck auto/man switch (stuck in auto). I tried moving the aperture gear and pushing on the pin coming out of the back of the lens but the switch does not move.

SMC lenses have a tiny pin around the lens flange that locks the A/M switch. When the lens is off the body you need to manually press it to unlock the switch. Maybe that mechanism is faulty?

Thanks, that was it!