[onecooler]

Hi All,

After I had crushed my revo build on 450 frame (a couple of month ago), I have finally found some time for the investigation. I assembled all the hardware on a new frame (old one got damaged badly because of altitude addiction) and have found a root cause of the crash. It happen to be a ESC failure. This was my first build and I did not know much about quad hardware, so I have purchased 20A HobbyWing Skywalkers and they seemed to do their job fine... until the crash. Now the failed ESC is partly functioning with the following symptoms: no initialization sound from motor, slow and shaky at start, motor runs at low power (it can be seen with a naked eye when throttling up), motor high heat. It is not a motor since I have tried 3 
At the first glance the ESC itself looks fine. And the questions are: what may cause such behavior? Would it be possible to fix this or I just have to throw it out of my window? (I have already ordered a couple of new ESCs, but it will arrive God knows when).

Thanks,
-K.

[Joe_D]

Hello, I got the same problem on my 400 quad, I fixed the damaged ESC by replacing one of the red glass diode then it was working as previously. On a 2nd thought I decided not to use it again, I would not risk another crash on a $300 machine to save $15 on a new ESC.

To me the problem occured because the revo+GPS was connected on the ESC's BEC causing an overheating of the analog voltage regulator. I bought a dedicated 3A switching power BEC and now it's working without problem. I also mounted the ESCs under the motors and propellers to improve the cooling.

Joe

[onecooler]

Thanks! I think I will choose the "window" option.   

[TheOtherCliff]

Jerky startup and very low power is a sign that one of the 3 motor wires is not connected.  That can be a bad connector, or a bad ESC component or a burned out motor winding.  Swap parts to determine where the issue is.