Order #721019 - Speedybee F405 V4 55a 4 In 1 - ESC failed one by one

Help Unmanned Tech
1

Order Number: 721019
Product Name: Speedybee F405 V4 55a 4 In 1
Brand: SpeedyBee
Summary of Issues with My 6S Build

:hammer_and_wrench: Hardware Setup:

• 6S quad with a 4-in-1 ESC. SpeedyBee f405 and 50A ESC

• DJI Goggles 3 + O4 Air Unit for FPV.

Frsky XRS RX

• Using a ribbon cable to connect FC and ESC.

:fire: Key Issues & Timeline

:one: Initial Power-Up – Motor Burned Out Immediately

• First time plugging in the battery, one motor instantly smoked.

• Other three motors seemed fine initially.

:two: ESC & FC Behavior After Motor Failure

• Used a multimeter to check the ESC → No shorts found between motor pads or battery pads.

• Removed burnt motor.

• Used a smoke stopper to test power-up:

:white_check_mark: 2 motors beeped and spun up in Betaflight.

:x: 1 motor didn’t respond.

• Connected to ESC Configurator:

• Only detected 2 ESCs instead of 3.

:three: ESC & Motors Gradually Stopped Responding

• After multiple power cycles:

:x: The working motors stopped spinning completely.

:x: ESC Configurator no longer detects any ESCs.

:four: FC Connection Issues

• FC LEDs light up when powered.

• Having trouble connecting to Betaflight via USB (only works sometimes).

:mag: What I’ve Checked So Far:

:white_check_mark: ESC has no visible shorts (tested with a multimeter).

:white_check_mark: FC powers up and LED lights work.

:white_check_mark: Checked ribbon cable

:white_check_mark: Removed ribbon cable and direct soldered between ESC and FC

:white_check_mark: Tested with smoke stopper (prevented full current draw).

:white_check_mark: Tried reconnecting multiple times.

:white_check_mark: Reflashed FC with clean install of Betaflight

:question: Questions for Troubleshooting

  1. Would a damaged ESC prevent all motors from working, even on good channels?

  2. Does the FC connection issue suggest power regulator damage?

  3. Could a faulty ESC cause gradual failure of the remaining working motors?
    https://youtube.com/shorts/jDqhvXNe-4M?si=P5HySwldHomBbxz1

Video link to issue here.

Image Description
Image Description3024×4032 3.8 MB

2

Hi Daniel good day,

Hi good day,

Thanks for reaching out to us!
Sorry to see you are struggling with your stack. What you are describing seems a bit odd, so I have emailed your description and video through to SpeedyBee and asked one of their engineers to give us some feedback.

As soon as I hear back from them I will update you.

Hope this helps.
If there is anything else I can help with please do let me know?

Regards,
David

Unmanned Tech Support

3

Thanks for the reply.

See what they come back with I guess.

Thanks

4

Hi Daniel good day again,

We had some feedback from SpeedyBee regarding your ESC. Would you be able to take some photos of the top and bottoms sides of the ESC for us and then also a short video documenting your MOSFET check?

I know you have already done both of these basically, they just want to confirm what is wrong with it I think.

The original response I received from Cathy at SpeedyBee is below for your reference:

To proceed with troubleshooting, could you kindly ask the customer to provide the following:

  1. Clear photos of both the front and back sides of the ESC.
  2. A screenshot of the order, which includes:
    • The store name
    • Purchase date
    • Order number

If the customer has a multimeter, please refer to the article below to check whether the MOSFETs on the ESC are functioning correctly. Kindly ask the customer to share the test results with us. (When measuring the MOSFETs, please make sure the motors are completely desoldered.)
How to use a multimeter to confirm if the ESC MOS tube is functioning properly

If the video exceeds the file size limit for sending, we kindly recommend uploading it to Google Drive and sharing the link with us instead. Please make sure to set the ‘General Access’ to 'Anyone with the link'.

Once we receive this information, we’ll do our best to support you and find a solution as quickly as possible.
Please don’t hesitate to let us know if you need any assistance during the process.

I’ll forward this on to SpeedyBee and try my best to get this resolved as quick as I can for you.

Regards,
David

Unmanned Tech Support

5

Thanks. I’m away this week so will have a look next week and send the info. Needed.

6

Hi, David,

Details below. Hopefully this is as expected.

https://youtu.be/J2_aVTC7wRM?si=kZC1JY85iqKWpPTn

https://youtu.be/jy0QFYnRGsI?si=DW2YQ-Uu88CUiO8n

Thanks

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7

Hi Daniel good day,

Thank you for the detailed videos, I really do appreciate the time taken there. I have sent these through to SpeedyBee and asked for their assistance.

As soon as I hear back from them I will come back to you with an update.

Again, I do apologise for the delays here.

Regards,
David

Unmanned Tech Support

8

Thanks, hopefully they can find a solution. I’m keen to get this in a quad and flying!

Cheers

9

Hi Daniel good day,

I had one of SpeedyBee’s engineers look into the fault you reported. They have confirmed a far as possible, what we both suspected, that there is indeed a defect/fault with this unit.

We do currently have stock of these, so I can have a replacement sent out to you or I can refund you for the unit. Please let me know which you would prefer and I can action that for you?

I do apologies for the length of time it has taken to reach this point.

Hope this helps.
If there is anything else I can help with please do let me know.

Regards,
David

Unmanned Tech Support

10

David,

Thanks for confirming. I purchased a second stack at the time m, so if you could issue a refund it would be appreciated.

Cheers