If you hear bad sound when the build plate, follow this video guide on how to solve it.

Many think that the bearings needs to be replaced, but they do not.


On this video you will see an early version with 3 bearings. The procedure with later version with 4 bearings is the same. 


https://drive.google.com/open?id=0BxVjjKHvPwU4b3BMNDZVY2F6X1U