I had the very same problem. It was the hall sensor so I replaced it today for another one and the problem was solved...but it lasted only one fligth. I will open it as you mentioned and check for a loose wire. If it is not: what I am doing wrong to break two hall sensors in short time? BTW:The engine is shaking quite a lot because is new and it is well grounded. [][].
Have you Keith´s e mail?
Thanks . Alex