I've come to the conclusion that the sound goes away when the drive reads or writes a disc. So when there is a disc inside and the drive isn't using the head (just the disc is spinning) I can hear the mentioned sound. It looks like the head is doing something inside in spare time.
Can any Sony CRX320E or LiteOn SOHC-5232K users tell me whether they can hear the sound or not?
War is peace
Freedom is slavery
Ignorance is strenght