so this has been bugging me for a few days now. was out flying my 5inch, nothing crazy just cruising around, and one of the rear motors just cuts out. quad tumbled, not a bad crash luckily landed in grass. checked everything visually and cant see anything obvious ? no burnt smell, no cracked solder joints that i can see, bell spins freely by hand.

plugged it back in and the motor twitches weird on arm, like it tries to spin and then kind of stutters and stops. the other three are fine. betaflight shows all four ESCs responding in the motors tab but when i push the slider on that one it just does the stutter thing.

running a blheli_32 4in1 so i cant just swap one ESC independently which is annoying. could be a winding issue in the motor i guess? or maybe one FET on the ESC is toast. not sure how to narrow it down without just swapping parts

that stutter on the motors tab while the others spin up fine is almost always the motor not the ESC in my experience. a shorted winding will do exactly that ? it'll try to spin, the ESC detects the weird back-EMF or overcurrent, and it just gives up. pull the motor off and swap it with one of the other positions and see if the problem follows the motor or stays on that corner. takes like 10 minutes and it'll tell you everything you need to know.

if the problem follows the motor, you're looking at a rewind or just buying a replacement. if it stays on the same ESC pad even with a known good motor then yeah you've got a blown FET and that's a 4in1 replacement situation which is a pain but what it is

had almost the exact same thing happen on my hyperlite motors last summer, turned out a tiny bit of grass got wrapped around the shaft and partially locked the bell. wouldnt have known from looking at it. worth checking with a bright light and maybe running a fingernail around the gap between bell and stator before you start swapping stuff out. probably not your issue but quick to rule out