Primary purpose is worn out capacitor. Remove mo yung cover a likod at may makikita kang component similar to what have been shown at the comment above. Pwede mo naman yan palitan on your own basta same value (uF or microfarads), same rating and same brand as much as possible. Make sure an kung paano yung position and orientation nung original Capacitor, ganun mo din i-install yung bagong capacitor.
Kung di umubra yan, may iba pang reason na madali lang naman solusyunan in a way, pero I advise you to consult a technician.