Weakened Fan Capacitor
A fan that is stuck or spinning slowly can also occur due to a weakened fan capacitor. This happens because capacitors have changed in value due to long service life. Weak capacitors are characterized by the drying of electrolyte fluid on the bulging physical part. But sometimes this condition is not accompanied by a physical sign of a bloated capacitor.
How to check capacitors can be done by using an analog AVO meter can be done in the way above.
If the capacitor has been confirmed damaged, then replace the capacitor with a new one. Replace old capacitors with new ones of the same size such as 1.2μ 1.5μ, or 2 μ or with larger capacitors e.g. from 1.5 micros to 2 micros.
Worn or Dirty Axle Rotor
The rotor ad is the part that is in front of the dynamo and serves to rotate the fan propeller. With a long enough use, there will be a buildup of dust and the loss of lubricant that attaches sticky ad with bearings.
To overcome it quite easily, clean dust and dirt and provide enough lubricant so that the ad rotates easily.