Has anyone ever had any issues with a Trutrak autopilot causing a high pitched whine in the audio system whenever the autopilot is engaged? I just put a Sorcerer in an L-39 and also a Garmin GMA-340 audio panel and whenever I engage the autopilot I get a high pitched whine in the audio system. It's not just a noise; it sounds like an inverter whine only this one is at about 4.4khz. I am positive that it comes from the servos somehow because whenever the pilot is engaged, you can actualy hear this same sound from the servos like there is some sort of high frequency inverter in them. The real kicker of this whole thing is that the sound gets into the audio system through the Garmin GDL-69 audio output to the 340. If that line is not connected, you barely hear the noise and only during radio or intercom transmission. I have relocated audio and data lines, moved this, grounded that, ungrounded the other thing and nothing helps. I have heard this noise one time before when I installed a Sorcerer in another jet along with a 340. That ended up being one of the headset audio jacks touching ground and was easily remedied. This one though, has me pulling my hair out. Even the Trutrak guys were stumped. They had no idea where this noise would even be generated. All the signals going to the servos are either straight DC or ground. This noise is somehow generated in the servos and is feeding back into the audio system, through the GDL-69. If the GDL-69 is not in the circuit, in particular the audio output, no noise. Any input on this would be appreciated. Thanks in advance.