Order Number: 715511
Product Name: Speedybee F405 Aio 40a Bluejay 25.5×25.5 3-6s Flight Controller
Brand: SpeedyBee
3 motors spin correctly but one twitches instead of spinning smoothly and the ESC will sometimes reboot. The motor feels fine and their is no visible damage to either component.
I have resoldered the motor to ensure a good connection. I have also reflashed betaflight and bluejay storing a backup of the original firmware.
Hi there,
Thank you for reaching out to us regarding the issue with your Speedybee F405 Aio 40a Bluejay 25.5×25.5 3-6s Flight Controller. I’m sorry to hear about the trouble you’re experiencing with one of the motors. Can you please also send a video showing the one motor with the issue not spinning smoothly?
Best,
Isel 
Unmanned Tech
Thanks for the response,
Wouldn’t let me upload files on drone trest so I’ve attached a video here.
(attachments)
Hello Jack,
Please see advice from the supplier’s engineering team:
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Please swap the motor that is working properly with the one that isn’t turning correctly, and check if the flight controller returns to normal operation.
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If you have a multimeter, please refer to the article below to measure if the MOSFET is functioning properly (ensure to desolder the motor during measurement). -How to use a multimeter to confirm if the ESC MOS tube is functioning properly
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Could you please confirm if this issue occurred when you first used it?
We look forward to your response.
Best,
Isel
Unmanned Tech
Hello Isel,
I have swapped the motor with one that was working and now get the behaviour in both motors even after unsoldering and resoldering all motors to check with the multimeter. Everything seemed fine when checking with the multimeter and there is no visible damage to the mosfets.
The AIO and motors where brand new and the behaviour happened the first time I connected the drone to betaflight.
Thanks for the response and ideas,
Jack
Any updates or new suggestions on this?
Hi
I am very sorry about this, it seems that the issue slipped through unanswered!
Does this mean, that when you put a motor that is working on another arm of the quad, onto the faulty ESC, then that motor does not work.
Similarly, when you take the motor that was not spinning, and connect it to another side of your drone, then it does work? Then this means the issue is on the ESC itself and not a fault of the motor. Once you can confirm I will pass this back to Speedybee to try arrange a replacement for you. However, in the meantime can you also please connect to ESC-Configurator.com and check that all the ESC settings are the same across all 4esc, just incase the one ESC has a different config, such as weird timing, or startup power wich can also be a cause for this issue, especially if you already checked the MOSFET with a multimeter, as this suggets its a config/firmware issue, rather than a hardware issue.
Hey Alex,
I swapped a working motors onto the arm with the issue and it had the same fault. However, the motor that was on there originally would not work on another arm even after resoldering. I checked the ESC settings before and also reflashed to make sure they were set up the same. I could double check though next week.
It seems strange that neither motor is working now, not sure what that could mean.
Thank you, I have sent this over to speedybee so hopefully we can finnally get this resovled.
I agree it is super odd as its still not clear to me if its the motors or your ESC at fault? When you tested the MOSFETS, did you have the motors connected or not? As this test only works when the motors are desoldered from your ESC
Kind Regards
Alex
Unmanned Tech Support
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Yep, I made sure to desolder the motors before checking the MOSFETS.
Thanks for the support, hopefully speedybee have a better idea of what is going on.
Thank you, and I am very sorry to ask yet another question, but Speedybee are asking if you can confirm the specific readings when doing the MOSFET check, as this will allow them to conclude the cause of the fault and hopefully authorise a replacement!
Kind Regards
Alex
Unmanned Tech Support
Join our community at dronetrest.com, or on Discord.
Thanks for all your help, turns out the AIO is fine.
I’ve damaged the motor windings with a screw which explains why the other motor started to display the same behaviour. I’ll get some more on order and hopefully next time I’ll pay more attention to what length screws I’m using.
Sorry for the time you’ve spent trying to resolve this issue,
Jack
Thank you for getting back to let us know. And happy to hear its not the AIO at fault, but also thanks for confirming about the motor issue, putting too long screws in and damaging the windings I think is something most of us have learned the hard way at some point along our FPV journey!
Worst one for me is actually replacing an entire stack on a build, only to find it still doesn’t work (turns out the battery I was using had such a low charge that it would temporarily power the stack/ESC but then disconnect randomly a few seconds later.). and I never thought to check the battery voltage while I was bench testing!
Kind Regards
Alex
Unmanned Tech Support
Join our community at dronetrest.com, or on Discord.