Ok gang, I have spent the last three days trying to research this issue. I have APM 3.01 firmware and 2.5 board. Everything loads and all the calibrations work perfectly except the radio.
I am using a Spektrum DX8 and AR8000.
All receiver channels work their respective APM mission planner radio calibration displays except the Yaw and ch5.
When I move the rudder the yaw display moves with the stick but I also get ch5 following. I have no mixing selected. Servo monitor shows no interaction between rudder and ch5!
Also when I hold the rudder full left or full right the yaw and ch5 cycle on the mission planner radio cal screen with the DX8 rudder stick held.
I even can disconnect the ch5 from the receiver to the board and it still moves on the radio calibration screen.
I even tried my Futaba radio and receiver combo and it does exactly the same thing. My guess is the board may be bad.
I checked the solder pads for the headers and there are no bridged signal pins!
I did a full reset, erased the eprom and uploaded the firmware and the problem still exists.
So to sum up:
Yaw channel and ch5 move together on mission planner radio cal screen
Checked for internal radio mixing and there is none
Servo monitor on both radios reveal no rudder ch5 interaction
Disconnecting ch5 from the FC does not stop the interaction
There are no bridged solder pads on the input headers
Trying to see if this is a software issue or bad hardware. Thanks for your input... Bert
Replies
Mine was off brand as well. I checked continuity on all the signal pins and found ch 4 and ch 5 were shorted! I sent it back and bought 3Dr board and everything works as advertised!
I am having the same problem, but it is an off-brand APM 2.5. I assumed it was a defect in the board somewhere where it can't be seen because I have 3 of the same board flashed with the same firmware and only one of them does that. It can't verify that is the cause, but it seems likely and may be what is happening to you as well.