DEC850 noise.

[Koloa]

In the last week or two, my DEC850 started making a soft rapid "chirp" sound (audio attached).  As I bought the unit in 2022 it's obviously going to be out of the initial warranty period (and I believe the model has since been upgraded to a "v2" anyway...

Given that the DEC850 is fanless, and there's likely no moving parts within it, does anyone have any thoughts as to what this sound could be, and, how worried I should be?  Likely electronic in origin, at a guess.  No, I haven't tried to open the unit up yet.  In terms of location, it seems to be towards the right edge somewhere, as you face the front of the unit (where the GB/SFP ports are).

Thank you!

[patient0]

There is a teardown on reddit: https://www.reddit.com/r/opnsense/comments/13iew8d/dec850_teardown_shots, but none show what's next to the RAM stick on the right.

The background noise in you M4A suggests that it's in a rack, are you sure it does come from the DEC850? Or maybe the power brick is placed on the right side and starts to go?

[Koloa]

Thanks very much for the reference for that teardown image!  It looks to me that the sound I hear is coming from what appears to be the RAM area, which is odd. 

The background noise is because this is in a well-ventilated closet in my flat and I had the window open nearby - the DEC850 isn't in a rack and there is no power brick near the sound area, there's nothing at all.  And picking up the DEC850 has the sound follow the unit, coming from exactly the same location.  Very peculiar indeed...

[patient0]

The background noise is because this is in a well-ventilated closet in my flat and I had the window open nearby - the DEC850 isn't in a rack and there is no power brick near the sound area, there's nothing at all.  And picking up the DEC850 has the sound follow the unit, coming from exactly the same location.  Very peculiar indeed...

I see, it doesn't sound good to my ears. I'm not an electronics guys, not sure what electrical component can make that sound (before it fails).

Maybe get in touch directly with Deciso https://www.deciso.com/get-in-touch/.

[Patrick M. Hausen]

Inductors are among the only components I am aware of being able to "chirp". Any one near?

[patient0]

The image on the product page, any inductors?

[Patrick M. Hausen]

Difficult to tell from the rendering. A photo of the real PCB would be better. But of course there will be inductors *somewhere* 🙂

[pfry]

Doesn't sound like an EMF-generated noise to me, but that may be a case of Memorex vs. live.

I have an old Haswell that whistles quietly under load (variable tone based on load), and has done so since I built it in 2015. It's my secondary server, so it's been running for ~10 years. The noise in its case originates from the CPU socket/regulator region (note that the Haswell has much of the regulator built into the CPU). My other three fanless machines make no audible noise (all four are fully self contained, including AC-DC power).