Crash diagnosis. 2nd servo failure?
This is my first post on RCU. I hope this is the right forum. My Mini Ultra Stick went in today for the second time due to what looks like on the surface to be a failed servo.
The plane is set-up with a tower-pro brushless motor, melody/dream-fly 25amp esc, a Dimension engineering SmartBEC, a GWS d/c 8 channel reciever, and a combination of 4 e-flite and 2 GWS servos. Battery is the Milehigh RC 2200 Mah 3 cell li-po pack. Several weeks ago during straight and level flight the elevator servo stopped responding and the plane went in. This was an E-flite servo that stopped working. After that crash I hooked everything back up and the offending servo would work for a little while and then just quit. But when it would quit sometimes some of the other servos would go nuts. Anyway I replaced the servo thinking it was just a bad servo that caused the crash. I also put in a different GWS d/c receiver just in case. I probably flew the plane 1-2 hours of trouble free flight time after that crash. Today during mid-flight the plane stopped responding and went in. This time it seems the right aileron servo failed. This was a GWS servo. When it failed it not only stopped responding but it caused full deflection and twitching of most of the other servos and no response to controls. As soon as I un-plug the right aileron servo all control surfaces go back where they belong and control is regained. I have plugged this servo into other channels of the receiver and it has the same effect on the rest of the system. If I plug one of the other servos into the right aileron channel it works fine as long as I don't plug in the one that failed. So again on the surface it seems I have a defective servo.
My question is what is causing this? I have a hard time believing that I have just had 2 bad servos. I'm scared to just replace the servo for fear of another one going out. Anyone have any Ideas of what else to check?