I have finished putting together a FlipFPV quad with an APM 2.5 with the external compass mod. I have used the APM on a tricopter with no issues before and in planes extensively.
Right now I am having a very strange issue. One of my motors is not spinning. In fact the ESC does not even initialize. I have tested each individually and they work. I have calibrated the ESC as well. I have checked the voltage input at the ESC and it is fine.
I am not sure what could be causing this. Is there a way to test the a particular APM output to see if it is working? Any suggestions welcome.