STEC 55x audio alerts

I have an STEC 55x in my Cherokee 235 coupled with dual Aspen and 430W. It’s a great autopilot but it is very sensitive to being out of trim. As such, when the trim up and down alarm comes on it is very loud. I understand it’s important to not overwork the servo but the audio often booms over ATC giving instructions while descending on approach before you can trim things perfectly. Anyone know how to decrease the volume coming from the autopilot relative to the COM audio?


  • edited September 2019

    Hi and thanks for writing. I have a 55X autopilot without auto-trim, too. I'm using a sonalert for sound generation. Is that what you're using? If not, post a picture. However, you can put a piece of masking take over the hole on the front of the sonalert and that will cut some of the sound down or you can put a resister or potentiometer in series with the sonalert to cut the voltage down and reduce the volume.

    Scott Sherer
    Wright Brothers Master Pilot, FAA Commercial Pilot
    Aviation Director, Piper Owner Society Forum Moderator and Pipers Author.

    Need help? Let me know!

  • The alert comes through the headset and I don’t see a way of lowering the volume independently through the audio panel. It sounds like I would need my avionics shop to do the things you suggest. My AP and audio panel are below.
  • You can turn the sound WAY down by removing the unit and there as an adjustment. There are two holes when you remove the unit search online so you choose the right one. I had to turn mine down like 3 full turns I believe. Yes, mine was louder than front row at a rock concert through my headphones. I changed audio panels and that caused my issue it was low with the old audio panel. You don't need to touch any wires or audio panel to make this happen and it takes 10 seconds once removed! My problem was I did not have the right screwdriver to remove it

  • Maybe send an email to STec/Genesys and ask them; I'm sure their technical support would be able to easily answer your question.

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