In addition to "Micro Cooling Fan" fixed noise itself, there are many sources of noise, such as: bearings due to lack of precision, improper assembly or poor maintenance can cause abnormal noise. In addition to fixed-noise fan itself, there are many sources of noise, such as: bearings due to lack of precision, improper assembly or poor maintenance can cause abnormal noise. Most motors will produce noise, some are "Micro Cooling Fan" poor design or manufacture of controlled goods caused by poor, but sometimes the cause inside and outside cooling fan motor. Most motors will produce noise, some are poorly designed or manufactured goods caused by poor control, but sometimes the cause inside and outside cooling fan motor. Gears and belts also produce noise due to friction. "Micro Cooling Fan" gears and belts also produce noise due to friction. Other structures of resonance noise arising should not be ignored, which is sometimes due to the imbalance caused by the body. Other structures of resonance noise arising should not be ignored, which is sometimes due to the imbalance caused by the body.