Hello to all. I encounter a strange problem. Although my Beosound 4 works perfectly, I have suddenly lost the clicking of the round sound button on the left, and when I touch this button the sound volume does not change anymore. I still can cut the volume when I press on it, as it should. Therefore, I can only change the volume via the remote control or if I go into the menu. The right round button works perfectly. But from time to time (very rarely though) the clicking comes back on this left round button and then disappear again. I have tried to unplug the BS4, went into the menu with no solutions, tried to activate the button in many ways without any success. Do you think it is a mechanical problem or is there a setting in the menu that should be activated through a specific process? Many thanks in advance for any help you may provide me with, as I don't know how to solve this malfunction.