Dyson AM09 malfunction

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I'm trying to fix my neighbor's Dyson AM09 fan.

The fan motor starts and stops after a few seconds.
I checked the motor. All 3 windings are identical in resistance. The shaft rotates freely by hand. When starting, holding the motor in hand I feel a soft vibration, which disappears when the motor continues to spin inertia after switching off. The motor can't spin up without the fan blades, it just vibrates and spinning at low revs.

The motor is BLDC, three phase with three hall sensors. The half-bridges are powered directly from rectified mains voltage. The signal from the sensors is getting to the controller board, the waveform is good - rectangular with a 120 degree offset.  The waveforms at the output of all half-bridges looks more or less the same, as well as the inputs of the drivers.

I disconnected the windings one at a time until I found one that does not significantly affect the motor behavior. I replaced the mosfets and the driver. The old mosfets were fine and after replacing nothing changed. I couldn't find a motor for replacement on sale.

The board is multilayer. I tried to trace hall sensor’s signals. 2 phases come to C and D inputs of 74hc74. the third phase goes to the microcontroller through a resistor. Controller board looks healthy, 5v on controller is stable and I can't find what the problem is.

Has anyone dealt with something similar? Any ideas what to try?
Would it be a good idea to try powering the motor from mains AC with a start capacitor to check a smooth rotation?

Thanks!