So I had the following setup on my benchtop and ran into a snag. I want to verify that there are no issues from the APM side of the hardware loop.
Problem? RcRx stopped operating after being powered (by 5.0V DC on the RcRx and 5V from USB on the apm2.0) in the following manner for 25minutes while running through mission planner configuration and configuring my RcTx toggle switches for flight modes. My main fear is a potential overvoltage or groundloop that damaged my ezuhf rcrx from overvoltage or a ground loop surge.
1) EzUHF 433MHz 8 channel (4.5-6V input) RC Rx: Powered through servo channel 8 by 5.0V VReg connected to Lipo
2) RcRx connected to APM2.0 through 5 female:female servo extensions from Rc Out (1-5)-> APM PWM Inputs (1-5).
3) Apm2.0 ALSO powered by the micro usb (~5v).
So, long story short, is there any potential risk from powering rc <-> apm pair with lipo AND usb at the same time? Or is this just an isolated incident where some component on my rx decided to die. I have a replacement coming this weekend and I don't want to fry it again if there is something wrong with my setup. This surprises me though because powering from lipo and usb at the same time seems like a common occurance.
Not sure about APM2, but in APM1, the rc power is isolated from USB power. I haven't look at the APM2 schematic, but one would hope that they kept it the same for APM2 as well. One quick test would just to power up the APM2 with usb power, and confirm that none of the equipment powered by the RC 5v rail is powered up.