[david_geng]

if you turn the spindle over the "dead zone" manually, it runs, but you can hear the jitter noise.

I've recorded a video showing the problems, and it is at http://www.deligeng.f2s.com/sx3.avi

firstly, I suspected the motor had fault. However, I measured the sensor output and the coils later. It looked alright.

So, should it be the motor drive board problem?

[HuFlungDung]

Is this a single phase motor, or what kind of thing is it?