Bose A20 old module(Pre-June 2015)

Welcome to Century Avionics Bose A20 troubleshooting site, please see below for help. If the below instructions does not resolve your headset trouble, please drop us an e-mail at

  • Only have audio in one earcup? Try the below.

    If only the Left Earcup has audio but the noise cancelling in the right earcup switches on(music/Bluetooth audio is audible in the right earcup) then confirm that the position of the Mono/Stereo dip switch is in the correct position. If the right earcup has audio but the left earcup does not then first confirm that the headset is the correct way around, if the headset is the correct way around then send the headset in for servicing.

  • Auto shut off not working/Batteries only lasting one flight

    If the batteries always go flat between flights (only if you don’t fly everyday) then test the auto shut off by removing the headset from the aircraft and switching the module on. The module should switch off between 5 to 10 min, if the module does not witch off then send the headset for servicing.

  • Bluetooth not visible

    If the headset is not visible to the device that you wish to connect it to then confirm that the Bluetooth LED is pulsing inversely with the power LED. If the Bluetooth LED is pulsing with the power LED then the headset is already paired with a device, to reset the Bluetooth depress and hold both the volume keys on the side of the module simultaneously for 10 seconds. Recycle the Bluetooth and it should become visible to the new device, if the headset is still not visible to the device then send the headset for servicing.

  • Headset making a pulsating sound when the module is switched on

    If the headset creates a pulsating sound that mimics the pulsing of the power or/and Bluetooth LED then confirm that you are not using Lithium, rechargeable or NiMH batteries. Use only Alkaline batteries, all other batteries may cause damage to the module.

  • Headset not audible by others or you cannot hear yourself/others

    If you can hear everyone in the aircraft but no one can hear you, or if everyone can hear you but you can’t hear yourself/them then swap headsets with someone in the aircraft and confirm that the problem transfers with the headset. If the problem transfers with the headset then send the headset for service, if the problem remains with the same person then the aircraft needs servicing.

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