Buzzing noise on my Giotto Cronometro V

Hi, i have bought a new Rocket Giotto Cronometro v, its about one year old now. It has a vibrating pump. And i recently noticed that the sound and noise it makes should not be like this, and may have changed iver time. It sounds like a machine that has some loose screws or pieces. But when i press the portafilter down when brewing, the sound stops and it has a smooth low/base noise which like, and probably should be. Do you have an idea where to check? Do i have to open it and tighten some parts or screws? Thank you!