Those elements forming "Micro Cooling Fan" dead? Refers to the so-called dead fan fans placed under some circumstances can not be launched under Rule viewpoint voltage. Test approach is to adjust the fan before each pole in turn placed a Hall IC, then the "Micro Cooling Fan" increase the voltage slowly until launch, less than before if the rules of each pole voltage start, on behalf of qualified, if uneven differences launch voltage exceeds the rule, known as dead. Influence "Micro Cooling Fan" launch feature voltage: 1. rubber magnets each magnetized pole uneven. 2.HALL IC sensor sensitivity bad. 3. Rubber magnets magnetized magnetic weak