Order Number: UT_9148-WH
Product Name: Speedy F405 V5 Stack
Brand: SpeedyBee
Product: SpeedyBee F405 V5 OX32 55A 30x30 FC & ESC Stack
Issue: Motors on ESC channels 1 and 4 are throttle-capped at approximately 1180 (out of 2000) and will not accelerate beyond this point. Motors on channels 2 and 3 operate normally at full throttle.
Diagnostics performed:
∙ Betaflight CLI confirmed correct motor resource mapping (B01, B00, B10, B11), correct timer/DMA assignments, and DSHOT600 protocol — all as expected for the SPEEDYBEEF405V5 target.
∙ Resolved a “Mixer mode problem — 0 usable outputs” error by resetting Betaflight defaults and reconfiguring mixer and motor protocol. Three of four motors then worked correctly; motor 1 remained capped.
∙ OX32 configurator (ox32.oxbot.com, v2.2.8) successfully read all four ESCs — all on firmware Rev.1.13, IO02-Rev.3.00, with identical settings across all channels.
∙ Exported and compared configuration JSON for all four ESCs — no differences found in any parameter.
∙ Reflashed ESC 1 firmware via OX32 configurator — no change in behaviour.
∙ OX32’s built-in motor direction and testing tool does not spin the affected motors.
∙ Physical motor swap test performed: motor from channel 1 was moved to channel 3 and spun up to full throttle normally. This confirms the motors themselves are healthy and the fault lies in the ESC power stage on channels 1 and 4.
Conclusion: Hardware fault on ESC channels 1 and 4 — likely damaged FETs or gate drivers. The ESC MCUs are functional (readable, configurable, flashable) but the power stages on these two channels cannot deliver full current. The flight controller is working correctly. The ESC board needs replacing
Steps are in issue description
Hi,
Thanks for the detailed testing so far.
From what you’ve described, this does appear more likely to be an ESC-side issue rather than a Betaflight configuration problem, especially since the motor itself worked normally when moved to another channel and the affected outputs also do not respond in the OX32 motor test.
That said, before we conclude the ESC itself is faulty, it would be good to rule out a few other possible causes that can produce very similar symptoms, such as:
- damaged MOSFETs or another ESC power-stage issue
- overheating or overcurrent damage
- a short from damaged motor wire insulation / contact with the frame
- connector or signal-path issues between the FC and ESC
- motor screw contact with the windings or other installation-related damage
As a next step, please could you check the MOSFETs using this guide here:
https://help.unmannedtech.co.uk/support/unmannedtech/ShowHomePage.do#Solutions/dv/221582000084906962/en-gb
In particular, please check for continuity between the motor pads and battery + / -, as unexpected continuity there can indicate a failed MOSFET.
If possible, please also share some clear close-up photos of both sides of the ESC, and confirm whether you can see any damage to the motor wires, solder joints, or signs of overheating.
Once we’ve got that, we can review it properly and advise the best next step.
Hi Alex,
Thanks for getting back to me so quickly! I can’t see any visible damage on the esc but it does have a plastic cover so they are not all visible. The cover doesn’t feel like it would come off easily. Unfortunately I don’t have access to a multimeter, but here are the pictures.
Let me know what I can do next to resolve this.
Hi Alex,
Let me know how I can proceed, want to order some more parts after this 
Thanks