[peter_4059 (Peter)]

Here's an example of the FFT plot for my EQ8. The X axis is period and the Y is amplitude. The peak at 200 is the worm period - ie 198 seconds for one rotation of the worm for the EQ8. The other smaller peaks are other elements of the drive system. You can use tools like the SKF bearing calculator to work out if the issue is worm bearing related or something else. In my EQ8 there is a 0.4" peak at 48.8 seconds. This is 4x the worm fundamental which probably points to Inner Race or Rolling Element defect. I've previously had a peak at 10s which turned out to be the meshing of the belt drive between the stepper and the worm. Tightening the belt tension fixed this. For comparison I've also included the pempro report for the same data.