so i had a pretty bad tip-over on landing last week, nothing catastrophic i thought, just one arm hit the ground at a weird angle. checked the props, one was cracked so i swapped it. but now when i spin up motors in betaflight motor test, motor 3 stutters and kind of pulses instead of spinning smooth. the other three are totally fine.

ive already tried swapping the prop on that arm with a known good one, no difference. the motor itself spins freely by hand and doesnt feel crunchy or anything. im wondering if i bent a phase wire connection inside the motor or if the ESC just took a hit. its a 4in1 ESC so i cant just swap that one channel easily which is kind of annoying.

anyone dealt with this before? is there a way to tell if its the motor or the ESC without having another FC to test against

classic symptom honestly. the stuttering pulse thing on one motor while others are fine almost always points to the motor not the ESC, especially after a crash. what usually happens is one or more of the stator windings gets a nick or the phase wire gets pinched near the base where it exits the motor bell. you can check continuity across all three phase wires with a multimeter ? should be roughly equal resistance between each pair. if one pair reads significantly different or open circuit, thats your culprit and the motor is toast.

if all three pairs read the same then yeah could be an ESC issue but that's less common from a tip-over unless it actually took a direct hit. had the exact same thing on my 5 inch build a few months back, swapped the motor and it was fine. 4in1 ESCs are annoying for this exact reason but usually they survive better than motors do in a crash

what motor is it? some of the cheaper ones the phase wires are really thin where they solder to the pads and a hard knock can crack the solder joint. might be worth just reflowing all three solder points on the motor side before you do anything else, its like a 5 minute fix and might save you buying a new motor