What should I do if the new piano hammer vibrates badly?

First of all, don't worry, the new piano is unstable for the first three months from your purchase to your home use. The vibration of your hammer is one of the running-in conditions of the new piano. Because the temperature and humidity in the piano shop you bought are different from those in your home, and the solid wood in the piano will definitely change after one handling. So don't worry, just debug the piano for the first time after 2-3 months. Generally, the new piano will not sound when pressed, or the keyboard will not rebound when pressed.

I hope my answer is helpful to you.