Follow up video answering question about what the output voltage of the induction coil is in an Oral B Vitality toothbrush.
After closer inspection of the components under the microscope, and some basic probing, my best guess as to the failure is the timer/switching micro-controller IC (6683041) has failed from water ingress into the toothbrush. Lots of visible corrosion around the chip.
I'm no expert of course, but it's the only component I can see on the board that controls the gate trigger signal to the N channel MOSFET chip (TSM7401) which appears to be switching the motor on and off fine.
Original Oral B Vitality Destruction Video: [ Ссылка ]
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