Hi Nellycopter,
Sorry for the delay in answering.
I was referring to the MR Head Lead Lag Dampers above. The weights under the floor are the Cabin Anti-Vibrators, sometimes called the Hammers.
As they are very frequency sensitive, sometimes they will not dampen out the 3 per as well as they can/should if the NR has drifted from nominal.
Have you had a track and balance carried out recently?
Rigidhead