Figure this is a relatively common problem so I’m putting together a thread on how the oscillating function breaks, how to fix it, and perhaps how to prevent it, or at least make the fan last longer before it fails.
The cause of failure on mine is the premature wearing of gears in the stepper motor which drives oscillation. Here’s some pictures:
These are the gears attached to the drive shaft and the first gears they interact with inside the stepper motor.
The part number printed on the motor is 28byj46-t026-12v
Why does it fail?
My thinking is that using the oscillation feature while having the fan set to an angle creates a moment arm that the housing doesn’t adequately brace. This introduces an angle and force between the gears of the rotor and the first set of gears they contact inside the motor.
To prevent this from happening, I think you would want to operate the fan in such a way that the housing is directly above and in line with the clamp; in other words, have the fan pointing straight into the room at a 90 degree angle, with no upward or downward inflection. When the fan is taken off of center from the arm, force is applied to the gears which causes premature wear and eventual failure.
Once I get my hands on a replacement motor, I’ll update the thread with the results whether it fixes it or not.
