Hi guys, need some help here.


I was flying my iFlight A75 HD indoors and after a "mild crash" I tried to re-arm the quad and get going but it wouldn't work.
I found out that the drone ended up stuck with one prop under a cushion so I suspect that when I re-armed and tried to fly the engine got damaged.

I checked the connection of the 3 wires and it was all good. Also, the typical sound when powering up the drone was still there and the engine was "vibrating"with the others. But when arming the quad, after a couple of slow spins, the motor stops moving and comes back to life only when arming again, and so on.

Assuming it was not a problem of the integrated ESC, I scanned the internet to find a replacement motor (IFlight XING-E 1103 8000KV) with no success. Only shipping from China.
I ended up ordering a set of 4 GepRC 1103 8500KV and yesterday I swapped all 4 motors, only to find out that the motor in the same position (back left) behaved exactly as the previous one.

Check the video HERE.

Any idea of where do I go from here?

"Assuming it was not a problem of the integrated ESC,"

And there you have it!    The symptom is classic two of three windings or two of three ESC outputs, and you needed to establish which before further expense.


There's always risk in faulting the motor/ESC pairing, but the first thing to do is to swap over the motor wiring with one that still works.  IF the "faulty" motor still won't run, swap back and test again.  That ensure that its motor OR ESC and the reversion gives confidence one has not blown the other.

Now?  Pretty certain the ESC is faulty

(25-Feb-2024, 12:03 PM)BadRaven Wrote: "Assuming it was not a problem of the integrated ESC,"

And there you have it!    The symptom is classic two of three windings or two of three ESC outputs, and you needed to establish which before further expense.


There's always risk in faulting the motor/ESC pairing, but the first thing to do is to swap over the motor wiring with one that still works.  IF the "faulty" motor still won't run, swap back and test again.  That ensure that its motor OR ESC and the reversion gives confidence one has not blown the other.

Now?  Pretty certain the ESC is faulty

Thanks, that's what I thought.
Instead of swapping with one of the current (new) working motors, I removed only the one (always of the new set) on the back-left position with one of the original motors.

Interestingly now the whoop does arm, but as I give throttle the quad jumps out of control...

Is it because I have 1 non-matching motor?

Sorry guys, I'm a total noob here, just trying to learn...

swap the motors to check esc and motor is good testing.
as you have a new motor and i doewng work as expected either. it might be the esc or the connection.

a blocked rotor under load can give backward electricity an fry motors or escs in such situations.

check the connection first, mesure by multimeter, solder it maybe if its a plug actual.

check the motors without rotors attached in betaflight configurator. we actualy just need to know if it does spin up well, in bfc without rotors works best for that.

if it doesnt spin up. you can try to plaster a hardware issue softwarewise in the esc configurator by the following;
increase startuppower, increase motor timing, set demag compensation to high.
dont do all at ones gently by steps on timing and startup/rampup power. demag compenation doesnt need caution.
if you can spin up the motor successfully than, give it a short flight and check the motors for heat. if it works but does heat up all motors a lot, it wouldnt work overtime than.

the quad jumps out of controll because the motor direction might be wrong on the swapped motor, you canset it in the esc configurator or in betaflight configurator in the motor tab

(25-Feb-2024, 12:50 PM)hugnosed_bat Wrote: the quad jumps out of controll because the motor direction might be wrong on the swapped motor, you canset it in the esc configurator or in betaflight configurator in the motor tab

The configuration in BF is unchanged, it was working before so it should work now.
Anyhow I checked again and the rotation direction is fine and the props are properly oriented...

Sorry for the silly question, but if I change motors, do I have to change anything on Betaflight?
Old motors: IFlight XING-E 1103 8000KV
New motors: GepRC 1103 8500KV

Just check rotation and make sure they are spinning the correct direction. Not all motors do. Some are wired to run CCW, but from what i've seen that is mostly on HM motors and they usually indicate by a red dot on the connector.

Aside from that no. Those motors are pretty similar, but the newer ones will probably eat Lipos a little quicker, giving you slightly less flight time.