You forgot to replace the spring with the little black plastic thing. It goes in the middle of the lower body part. When connected correctly it serves as a wheel stopper / position holder. After that, you insert the inner mechanism. It should make a nice clicking sound in contact with the spring held plastic. Then you attach the top part.
@@MomentsPlaces I opened it because I thought the batteries were faulty. Turns out it was the part at the 3:18 It wasn't getting fully in contact with the rotor. Fixed it by inserting a piece of plastic between the two clipper parts, thus making it closer to the rotor. Hope it helps someone.
