ANR shutting off during flight

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SSR

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Nov 27, 2020
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SSR
Strangest squawk I've ever had. My wife was wearing a very old pair of Bose X and said the ANR kept going off, randomly, inflight. New batteries installed, same problem. After it shut off, she'd press the power button and it would come right back on, green light and all. No pattern recognized, such as amount of time, or amount of speaking, etc. I figured the headset was old and giving up. Upgraded her to a brand new Bose A20, out of the box. Same thing happens! Then, I have a friend this past weekend, in a different seat, wearing a different pair of brand new A20s and it happens to him too. It's never happened to me, at my seat.

I tried to check with Bose and they asked if anything had changed on the plane. The only thing I can think of is installing a new Garmin audio panel in early 2020, but this didn't start happening right away. The avionics installer isn't buying that as the problem, it seems. He suggested shutting off the "auto-off" feature, which you can do on a switch in the battery compartment.

I'll give that a try, just to see if the issue stops, but I really want that feature left on, for obvious reasons. Any guesses what could be happening? How do the Bose know to auto-shut-off?
 
SSR said:
How do the Bose know to auto-shut-off?
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I believe it works off "activity" of the headset and will power off if it senses no audio or voice after x minutes. Turning the auto off should fix your problem.
 
Its logic comes from the VOX circuit. No voice activated com after so many minutes, its shuts off. This was happening on my A-20s when I first got them. I eventually realized that in a single seat aircraft with 1 radio and no intercom, the auto shut-off feature was indeed the culprit. I disabled it with the little switch in the battery compartment. No problem since.

I take the headset out of the aircraft and remove the batteries after each flight. So, no concern about remembering to shut it off.
 
RussR said:
Not on topic, but I'm just curious as to why?
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That way I know its turned off. And also, its the most fool-proof method I know of to protect a high-dollar AA powered device from being ruined because of a failed/leaking battery.
 
I just don’t think it’s actually the auto shutoff due to inactivity thing…the OP did say it was his wife’s headset that was acting up. ;)
 
MauleSkinner said:
I just don’t think it’s actually the auto shutoff due to inactivity thing…the OP did say it was his wife’s headset that was acting up. ;)
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I wanted to go there but thought better of it.

Many years ago the local paper had reported someone finding a very old skeleton. The article stated that nobody seemed to know how old it was or whether it was male or female. My dad looked at the picture in the paper and said, "it's a female." I asked him how he knew that from just looking at the photo. "Easy" he said, "the lower jaw bone is wore out." :)
 
I had the same issue whenever I used some of the free batteries from Harbor Freight. My battery tester showed that they were fine but when I used another brand, the problem went away.
 
Bose materials say the auto-off feature will activate after 3-9 minutes of inactivity. It does not explain what that means. No VOX, no audio input? The wide range is perplexing too. My avionics guy thought it listened for engine noise, but that didn't sound right. I was wondering if it knew whether the audio panel was on, but he refuses to believe that could be it.

The battery theory is worth exploring. They'd all have name brand batteries (don't recall which), but sourced from Amazon. Counterfeit?? It is definitely possible they all have batteries from the same batch, as I buy them in bulk.
 
SSR said:
Bose materials say the auto-off feature will activate after 3-9 minutes of inactivity. It does not explain what that means. No VOX, no audio input? The wide range is perplexing too.
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If recall correctly from a Bose tech, the "activity" is based on both voice and audio inputs to the headset circuitry. The auto off range was dependent on type of last input whether voice or audio and I believe the level of the input. I dont remember which input or level was at 3 or 9 minute side. We tried Bose in several vip helicopter setups and had similar issues. Connecting to aircraft power should also correct this issue.
 
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