Txs for your help and I wait your feedback for the knob.

Concerning the replacement, I will see after I open (one more time..) the empag. I also read that it was really hard to do this change. If I am not able I will either ask to eletronics/engineers friends or send it to somebody (Rob maybe). Do you know if there is a repair center arround London (I need to go there in 2 weeks)?