Problems connecting ESC to Omnibus F4 v6

Hi,
I run ArduRover 4.0 on the Omnibus F4 v6 board. Everything seems to be working as expected (i.e. SBUS, SmartPort telemetry, GPS and compass) but for some reason I can not power both the board and separate ESC from the same battery. I can power the board just fine without the ESC but as soon as the ESC is also connected to the power loop, the board shuts down. If I plug the ESC in first and then the battery, the board does not power up at all. If I start all over without the ESC the board powers up again. It makes no difference whether the ESC 5V and signal wire is connected to the PWM/servo pins or not. I have tried several ESC:s that I know are all working but the problem persists.

I have received some help from Lee at Painless360 and he can see nothing apparently wrong with the wiring. Perhaps I have a faulty board…?

I would like to know if anyone has managed to power a separate ESC on this board or are experiencing the same problems that I have?