@loly
Look on pcb for small chips maybe 3 pin up to 8 pin
Take number from chip with magnifying glass and google
When you find a chip that's called regulator or battery management ic then you found him.
It should be close to input power from mount or usb or maybe close to battery connector.
Also look for surface mounted pico fuses (very small) maybe labeled f1 f2 etc.
It's sad to lose a perfectly working 3490 for such a small fault.