Compressor doesn’t always want !!! SLK 230K Bj 99

Moin,moin Have the problem that the compressor sometimes doesn’t use to notice through power hole or stop when you look at it and increase threshold does not turn the disc with it, swallows itself rather. Is there a way to save something else on the compressor or can you say that the thing is gone? If I understand it correctly, the compressor switches on through a magnet, with increased threshold (by the “vibration force”, right?. Should you be able to repair it then how? Thanks for d he Help Greeting Mike