Thanks a lot. I understand clearly your suggestion. That was my initial guess but I needed confirmation. You know, this dead cap was placed like that in the factory (manual operator?) and the manufacturer does not want to give me the right answer in its forum, while implicitily suggesting they did something wrong. The only thing that I still try to understand is the way the cap died: it was slowly, the buzz grew day by day, slowly. By reading a bit on ELKOs, if the inverse current/voltage they are applied is low, they survive and behave like shortcuts. Since the other cap C8 may take over the whole voltage, the C7 was nothing but a useless piece. Then, it started losing properties and finally died. I wil replace it (with the right polarization) and keep on jamming...