Kakute F7 V1.5 Smoked, should I keep flying it?

Hi All,

First post on dronetrest. I flashed an RSSI mod firmware on an FS-X14S then on my first test I smoked the FC. To be honest I don’t think it had anything to do with the receiver firmware but whatever happened I see a relatively large component on the FC is discolored and swollen up and it is roughly where I saw the smoke. See photo below. I actually don’t know what the component in, maybe someone can help me identify it and what’s its purpose is?

The FC is still working when connected to a computer and the ESC is talking to the FC fine. I am planning to desolder and resolder everything on the FC and try flying it again while I wait for a new F7 controller.

Just want to know if anyone knows what that component is (the Kakute manual shows a “coil-like” symbol) and what impact it will have to the function of the FC.


Yep that’s an inductor which is usually part of dc/dc buck converter circuit (switching power supply). In your case it’s 10uH smd inductor (there was 100 stamped on it, at least that’s what i can see on holybro’s site), not sure which dimensions, you can measure, but i would presume 0630 size ( 773MM). If it’s part of 5V power supply, check if you get 5v on the pad next to it. I would still replace it before flying.

edit: hmm looks smaller than 0630 … i’ve measured usb connector which is 7.5mm so this is smaller… measure it, then we can see what size it is.

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You can try and replace it if your up to the challenge… I would just bin it.
I wouldn’t be happy risking my quad.

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Hi Gero, thanks for your interest and help.

I may try to replace the inductor as a side project. Although I have never tried to replace any sort of SMD.

Actual size is: 4.28 mm x 4.28 mm.

I am trying to look for a replacement on DigiKey.ca. How did you figure out the inductance value (what’s the 100 referring to)? I know the 5V rail is rated for 2 amps so i’ll be selecting something slightly higher i guess?

See catalog here: https://www.digikey.ca/en/products/filter/fixed-inductors/71?s=N4IgjCBcoEwAwA4DsVQGMoDMCGAbAzgKYA0IA9lANrhwAEArQBIgC6pADgC5QgCqAdgEtOAeUwBZQtnwBXAE6EQAXxVA

I am curious what might have caused this. Is it almost certainly from some short circuit on the 5V?

It looks like it’s 0420 size then, like 4 x 4 x 2 mm. that 100 on inductor is in uH and it’s like first 2 digits multiplied by 10 exponent third digit … so 10 * 10 ^ 0 = 10 uH . Chinese sell them cheapo like f.e. https://www.aliexpress.com/item/4001272524741.html ,on digikey the closest i’ve found is https://www.digikey.ca/en/products/detail/bourns-inc/SRP0420-100K/11688731 . What caused it, well low quality chinese components, 5V overload, if you’ve just reflashed rx, and it’s on 5v rail maybe resoldering created short … did you check with multimeter? Whenever i solder something, i always put multimeter in conductivity test and check if positive and negative are in short … who knows, did you check if you have 5V on fc ?

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