Reversed polarity RaceStar StarF3s



I’m a supernub in this area FYI.

I recently bought parts to build a FPV racing drone… The build came along with out problem (well apart from “noobsoldering”) and I managed to fly it a bit.
After testing it out I saw that the soldering on the XT60 connector had fallen off and without thinking I took it apart, cleaned it and then soldered it back together. I plugged in my 4S battery and I heard some sparks. My XT60 connector got burnt and so did my battery which has only 3 cells left after I checked it (I’m going to bin that battery… It is not swollen etcetc.). After I plugged out the battery I saw that I had soldered the positive side of the XT60 to the negative side of the StarF3s 4 in 1 ESC, BEC and vice versa. So I plugged in the battery backwards… (dumb me)

After removing my XT60 connector from my board I have checked for continuity which exist between my Positive and Negative pads…

I’ve researched for solutions but I have not found any yet and thought I might ask you PRO’s out there

What should I do?

My initial thought is that this board is fried and it will be impossible (?) to change for example ESC’s in it because they are so tiny and because of that I will have to bin it (or hang it on my wall so it will be a reminder off what stupidity can lead to). But is there any possibility it can be something else causing this continuity between positive and negative? If so please help me solve this, what should I look for and where should I start?

Is there any guide/tutorial that you know of that shows how I can check if my other components (camera, transmitter, rx etcetc.) are still working?

Thank you very much!

The flight controller I’m talking about is:
Racestar StarF3S 30 a BL_S 4 1 in ESC 5v BEC w/ F3 Flight Controller AIO OSD BEC


Yeah bad things happen.

I toasted a brand new ESC cause I put it on backwards… It happens to all of us.

Your ESC is toast… The rest of your hardware is probably ok I suspect the ESC took the main blow.
But you wont know for sure until you connect it all back up to a new ESC.

You could try and connect up your other parts on there own to a power source with the correct voltage.
Camera + VTX would still show an image on your FPV Display.
Rx would bind to the Tx (I Think).

Happy repairs.


Thank you for the reply and guidance. I will do so :slight_smile:


Yeah it happens to all of us… particularly when working late at night :stuck_out_tongue:

But its hard to know but I do agree with @DoomedFPV, that its likely just the ESC that is blown. One easy way to check the FC is to connect it just via USB, and if you can connect to it, and read sensor data in betaflight its a good chance that it survived,


Yea haha… well I wont do it ever again, we learn from our mistakes!

Yea I checked it via USB and it worked perfectly but its a 4 in 1 ESC built in so I will use it as a practice board haha… :slight_smile:


That is one of the downsides of a fully integrated board, makes it nice and easy to install, but if one thing on it breaks, you gotta replace everything!

But no harm in having a practice board