  A number of weight anomalies have been reported in the past with respect to
gyroscopes. Much attention was gained from a paper in Physical Review Letters,
when Japanese scientists announced that a gyroscope loses weight up to
$0.005\%$ when spinning only in the clockwise rotation with the gyroscope's
axis in the vertical direction. Immediately afterwards, a number of other teams
tried to replicate the effect, obtaining a null result. It was suggested that
the reported effect by the Japanese was probably due to a vibration artifact,
however, no final conclusion on the real cause has been obtained. We decided to
build a dedicated high precision setup to test weight anomalies of spinning
gyroscopes in various configurations. A number of error sources like precession
and vibration and the nature of their influence on the measurements have been
clearly identified, which led to the conclusive explanation of the conflicting
reports. We found no anomaly within $\Delta m/m<2.6 \times 10^{-6}$ valid for
both horizontal and vertical orientations.
