HP Elitebook Dragonfly - high frequency "electric" sound

[nskiselev]

Hi all,

I've bough HP Elite Dragonfly (9FT26EA) this week and I've noticed  the following problem.

When I instert USB device (e.g., a USB-flash drive) into my notebook, I start to hear very annoying high frequency "electric" sound coming somewhere from USB-C / USB ports. It is very easy to hear when an Ethernet adaptor is inserted into a USB-port and I download data. It is definitely not the fan (it is not spinning when this electric noise is in place). However, if I insert another device into other USB (type-C) port, then this electric noise becomes much quiter.

I see other posts from people who are experiencing analogous issues (e.g., https://h30434.www3.hp.com/t5/Business-Notebooks/HP-ZBook-G5-making-strange-quot-digital-quot-noises...).

I've made a video (https://vimeo.com/394650186) where one can hear this high frequency sound (Dell DA300 Ethernet adapter is plugged in) until I plug in my iPhone via USB-C cable.

Does anybody know what can be done to get rid of this high frequency "electric" sound? It is very annoying.

[MaDDigital]

I have the same exact sound experience with my 2 HP Dragonfly devices from work. Since working from home the last month, i noticed the sound echoing off my wall in the office and thought it was my monitor until i heard it without the monitor on.  Looking closer the sound is quieter but still present with no USB devices plugged in but gets louder with any USB device transferring data.  The sound is exactly the same on my 4K i7 Wifi model and my 1080p i7 4G model so I do think its something to do with software or a hardware flaw. I cant say that I noticed it the first months of the year but I was not consistently working with them in the same quiet environment to notice until now. 

Thanks for posting and getting a video. I messaged my HP engineer partners to see if they have an answer. I dont think a warranty replacement will fix this since both of my units have this and they were purchased over a month apart (Nov 2019 and Jan2020)

[nskiselev]

Thanks for sharing this information with me. If your HP engineer partners reply, I would be grateful if you could post relevant information in this thread.

BTW - I have some additional information. I learnt from HP telephone support one trick that helps, but only for some time. You should disconnect all peripherals from your HP Dragonfly and then turn it off. After that you should press the "Power" button for a long time (don't remember for how long exactly, but maybe 2 minutes). According to a guy from HP support this helps to "release the energy from condensers" on the motherboard. And, indeed, it helped, but then the issue occurred again (after 3 or 4 hours of use).

On March 2, 2020 I gave my laptop to an authorized service center (HP does not have its own service centers in Russia). I know that this service center order a new motherboard for my HP Dragonfly, but I did not receive my laptop back yet (for obvious reasons - COVID-19, quasi-quarantine in Russia and so on).

Hopefully, I will get it back in June 2020.