Originally Posted by theothercliff
I suggest that you either have better power (cleaner, correct voltage, adequate current) coming from USB than from your other source (that is why I suggest that you try a different, clean source like linear BEC or nicad attached to M1) or that connecting clean power to the USB connection would make the whole thing work (that is why I suggest you connect USB power to M1 power).
Ah yes I see that. I will give that a try However my replacement board works ok on the same quad
But I will test as you suggest