FritzBox 7362 SL high-frequency sound


I now own a FritzBox 7362 SL. I was able to successfully install OpenWrt. Now I have the problem that after ~ 15 seconds it emits high-frequency sounds. With the original firmware I do not have this problem!
What could be the reason? Can I do anything to stop this?

Anthony Stark

I experienced the same behavior on my FritzBox 7362 SL.
With the original software no sounds could be heard from the device.

So, I can cofirm your observation with a box running openWRT 21.02.3 snapshot and openWRT 21.03.0.

I don't think this noise (coil whine?) is necessarily a problem on a technical level. It is more just dusturbing for persons close by.
Since the device is located in my living room I will most probably switch to another device, due to these HF sounds.

Side note: A 12V/1A PSU died resently while supplying the 7362 SL. It could be just coincidence, but if someone else also experienced dying PSUs this could be important. With my configuration the average power consumption is at ~5W.