One downside with 4in1 ESC is that if one of the ESC’s fail, the whole board has to be thrown away. But you can actually “fix it” by replacing the broken one with a separate standalone ESC. This can potentially save you money and time to replace the whole thing.
Perhaps it’s not totally accurate calling it a fix, it’s more of a work around.
You can probably fix a broken 4in1 ESC by replacing the damaged chips on the board if you know how to. But it’s way too technical and time consuming for ordinary users. In my opinion it’s not even worth the trouble doing it than replacing it with a brand new board.
If one or more ESC’s stopped working in your 4-in-1 ESC board, you can simply replace it with a single ESC!
Requirement: the ESC you are replacing must support the same ESC protocol as the 4in1 ESC.
You might be able to get away using any random ESC’s that share the same ESC protocol. But it’s best to match the voltage, current rating, or even brand and model to minimize the chance of something might go wrong.
If you have similar experience, please let me know your setup below so we know what is compatible with what :)