All of a sudden, my TH9X transmitter (stock Iris+) starting sounding a constant high-pitched tone when the Iris+ is plugged in. I actually think the alarm (?) is coming from the frSky DJT module on the transmitter.

I've tried new batteries in the transmitter with a full charged battery on the Iris+. I've looked in the Iris+ and all seems okay and plugged in. I do get the TX and RX to bind just fine Even with the alarm, the Iris+ will arm and thrust can be added (tested without props). This is on a 2 week old Iris+ with 5 previous flights with no problems.

I've looked in many places, but cant find or get an answer. What does this steady tone mean and what do I need to do?


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  • Hi Larry,

       Double check and make sure all the switches/toggles are in the correct (up) position prior to connecting the battery for the IRIS+. 

    Todd H.


    • Thanks for the idea. All switches are in the "up" position. Throttle is down and centered. Roll/Pitch is centered.

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