Focbox mosfet explosion

Hi guys, do you think I can fix that ?

The focbox was pretty new, only used 2 or 3 times…

I wouldn’t trust that pcb, even if it could be functional again

Hi, when a direct FET is blown in this way (violent I guess would be the best word) there is no exact way to tell if it is repairable until the FET is removed. This is because it all deprends on the pads underneath it. If they survived then yes you can repair it fairly easily if the pads are burned away then you can not really repair it. Also there might be other traces that are burned so check that too.

EDIT: first step would be cleaning the PCB with some alcohol and examining the it further.


What are your battery and current limit settings? FOC?

Well looks like you already cleaned away a much bigger mess there. Did you throw it in a puddle under load? Looks like it got destroyed from shit coming in

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Yeah it looks like some water damage, you can see the case has a stain too in the background.

i peed on it. I was skating along, just peeing on everything like i always do, when i saw him riding around and I peed on his board. I made sure to get the back real good by the phase leads and i also hit the box a few times before i had to make a quick getaway.


You shouldn’t take a piss at every thread you see, and your tag should definitely not be a “pissing skater” :point_up_2:

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well seems like you ate sand again and peed it all over this thing… I already see @JohnnyMeduse cleaning up that mess…

I name you,


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don’t think this is salvageable, looks like it was exposed to salty road juice.

copper looks blown away

Why does the PCB area with mosfets look weird like it has liquid damage or something? What voltage did you run this at?

there was definitely water/crud ingress. That’s probably what blew it up.


i wouldn´t use it anymore, even if you change that mosfet, you still have corrosion on all other pads, which will lead to more faults like that in the future.

I think that you will need to replace all 6 because it is possible that if they are not dead yet they are on their way. The one you circled has most probably burned the pads underneath so remove it first, if it is good you may be able to fix it. So as of now you most probably have 6 fets, gate resistors and possibly DRV (maybe not if you are lucky, sometimes fets dont destroy DRV when they get damaged)

Salt water ? That’s a possibility :sweat_smile::laughing:

All fet seems damaged :confused:

Will do something more waterproof next time !

Yours dont seem to be as bad as OP`s

OP’s ? and how to desolder that shit ?

OP = original poster, the person that created the topic/thread

Hot air soldering station/iron is the right tool for the job.