Mine stopped switching to speed 2 and 3 after one or two years of mostly sitting plugged in, used it rarely...
I looked at the internet, disassembled the thing, looked at the control board and decided to make my own instead of going the warranty road.
It has cheaply engineered board that constantly producing heat with its voltage divider substitute for low voltage power supply.
So I manufactured my own control board of the same size with the same connectors around Arduino Nano module and proper power supply module.
It works with original remote and has buttons and indicators in the same place.
Even experimented with audio signals to indicate different modes (speed 1, 2 3 and timer 1, 2, 4 hours).
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Even 3d printed a new cover and a grid for lights:
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Works for two years already. And if something goes bad again I have enough parts left to fix it really quick.
Needless to say it is a less fire hazard too as it does not heat as much.