My one blade died, thought it was the upper fet which I replaced, but now when I connect the power supply I hear a buzzing noise from the power connector and the power supply goes off, have checked the boards for shorts and nothing I can spot, any idea's ?
maybe the 16v 220uf Capacitor.
I suppose you also replaced the ferrites/0 ohm resistors that burned with the upper gate mosfet.
There are very few components between the power plug and the mosfets, so they are easy to track:
Plug -> ferrites -> capacitors -> mosfets
You can check the 8 chips schematics on github for some help. It's almost the same as what we have on the blade.
I posted a few test points you can check in this thread. It can help finding the origin of the trouble.
Was a dogdy FET I replaced with, power now works, but looks like the Micro controller is fried now, does anyone have the firmware for the STM32F103RCT6 ?
Could also be that regulator that you guys are talking about, will have to check that tonight.