You have a wire loop (battery power).
This is certainly causing compass deviation.
Connect to Mission Planner and watch the compass output when you rise throttle.
hi, i changed the battery but it's same. How can i find this "wire-loop"? i don't know where to check. I don't know how to read compass data while flying. I made a log file, could you help me find the compass data?
Thanks so much for reply
cannot resolve! please say me what i must do, i'm very much frustrated!!!! i cange ALL parts.. i buy another apm kit presoldered but nothing :(((