Bose A20 Aviation 2015-present Owner's guide - Page 32

Troubleshooting Problem What to do Squealing or whistling sound when the headset is turned on Low rumbling sound with the headset turned on in a quiet environment • Make sure the headset orientation is correct. Use the Left (L) and Right (R) markings above the earcups to orient the headset correctly. • Inspect the seal between the ear cushion skirt and the earcup. The skirt should fit into the slot on the earcup with no gaps. Replace any cushions that appear to be worn out. • Adjust the earcup fit to create a better seal on your head. The headset's low-force design makes it sensitive to items that interfere with the seal around your ear. Make sure your ears are completely inside the ear cushions, and that a hat or eyeglasses with thick temples do not interfere with the seal. • If the squealing or whistling sound persists, turn off the power switch and contact Bose for service as soon as possible. • Adjust the earcup fit to create a better seal on your head. The low-force design of the headset makes it sensitive to items that interfere with the seal around your ear. Make sure your ears are completely inside the ear cushions, and that a hat or eyeglasses with thick temples do not interfere with the seal. • Check ports at the outside surface of each earcup to ensure that they are not blocked. If dust or dirt is present, carefully remove the debris using tweezers. Do not blow out or vacuum debris. • Inspect the seal between the ear cushion skirt and the earcup. The skirt should fit into the slot on the earcup with no gaps. Replace any cushions that appear to be worn out. Crackling sound audible with headset turned on in a loud environment, or Acoustic Noise Cancelling® noise reduction is intermittent • Make sure the headset orientation is correct. Use the Left (L) and Right (R) markings above the earcups to orient the headset correctly. • Adjust the earcup fit. Refer to "Wearing and adjusting the headset" on page 15. • If your headset is battery-powered, check to see if the battery is low (indicated by fast blinking red LED). • If your headset is aircraft powered, make sure the voltage powering the headset is no less than 10 VDC. • Inspect the seal between the ear cushion skirt and the earcup. The skirt should fit into the slot on the earcup with no gaps. Replace any cushions that have surface tears, torn stitching joints, large wrinkles, or have become dried and stiff. Warning: If the headset emits any loud noise and ­related loss of communications while in the Acoustic Noise ­Cancelling mode, turn off the power switch. The headset will continue to provide communications in the passive noise reducing mode. 32 - English