BobK207 wrote:
The guys in this ng (myself included) are going to need a lot more
detail to pin point the cause of this behavior

But w/o the info, IMO this is a problem of inadequate floor system
stiffness.

It is different than the squeaky floor problem.

I'd guess that the floor joints run parallel to the wall that the
china cabinet is up against. I'll bet that the TV cabinet is arranged
similarly.

What size are the floor joists? what is their spacing? how long is
the span (unsupporte length)?

Without knowing all the details, these ideas are just guesses.

If the hypothesis is correct, the solution is to stiffen the floor
joints.
The exact method of stiffening would be dictated by the details of the
as built condition.

The fact that the floor is over a basement will make fixing the
problem much easier.

You can search this ng for similar recent topics
cheers
Bob

To add one thing to Bob excellent post, the reason the first floor is
less stiff than the second floor is because the second floor likely gets a
little help from the ceiling on the bottom of the structural members.


--
Joseph Meehan

26 + 6 = 1 It's Irish Math