I have a Trex 600 CF, I have setup all of the avionics correctly and they work properly with just the BEC on. When I Plug in the main battery and engage the motor the elevator servos no longer respond correctly, it's like it goes dead. There is a catch though, sometimes the elevator servo deflects to a full aft or nose up position. I have tried switching the RX from an FM to a PCM and same issue. I fear it's some kind of interference from the motor but if it is I am not sure how I would fix that. Any ideas? Here are my specs.

Align Trex 600CF Combo Version
Futaba GY 401 Gyro
3 Futaba S3151 Digital Servos
1 Futaba S9254 DigitalTail Servo
Mavrikk Carbon-fiber main blades
Mega Power 4400 Mah 18C 6S2P LIPO Battery
Futaba 9Z TX
Futaba FP-R309DPS RX.

Allow me to answer my own question. Out of curiosity, I pulled the main rotor blades and bench hung a Futaba S3004 servo plugged into the ch. 2 elev slot on the RX. When I spun the motor up, all servos function as advertised. I then pulled the digital servo out of the frame. In looking closely, I found that the white signal wire had been chafed through the insulation, and had been contacting/grounding out on the carbon fiber frame. This was covered up by the tywrap that secured the servo lead to the frame and away from moving parts. It is my theory that the RF noise created by the motor fed directly into the servo signal wire via the carbon fiber frame, thereby rendering it inoperative until the noise/interference ceased. At least that's my story and I'm sticking to it.

Good catch...so is the issue cured?

Absolutely Raserx, I reinstalled the digital servo after applying some shrink wrap to the injured wire and re-securing everything, presto, I'm airborne. That was indeed the problem and fix. I hope this finds the eyes of anyone that experienced this in the past present and future.

Good job finding the problem! Excellent troubleshooting! That one had me scratchin' my head a bit... [&o]

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