Edit: I don't know what happened with my text, so I pasted it here:
Hello,
It is a 4-wire PC PWM Fan that I broke by swapping the GND and 12v for 2-3s. I did it because I thought it could reverse the direction like in other motors. So, something is dead in the fan.
I remove every case and just leave the circuit with its inductors (pics), and its blades (without pics). Also, I provide pics of the main chip in the circuit (using a cheap microscope).
Some friends said to me that probably the chip or the diode are broken, but studying the chip would be really hard, and without the real numbers in some components would be almost impossible to replace it.
I have more pics if it is necessary. Also, I can take more. I think the chip is K408 Y331, or something similar.
I was searching for variations of this chip and found almost nothing, just the Y836.
I would like some help to get any of these:
a) How can I repair this circuit? How can I get the broken components?
b) In case the a option is almost impossible, How can I reuse the motor + blades? I can desolder the 3 legs of the motor, and start from zero, but I have seen many different tutorials on internet that maybe are not applicable for my 12v 0.3A fan with 3 legs. I would like the easiest way (Arduinos? ESC? new custom circuit? any chip?).
Thank you