Static noise from a new laptop Pavilion 15z-eh000

[alvinyun]

I bought a new laptop Pavilion 15z-eh000(Product number: 9WD42AV) in December 2020 and I found it may be defective on arrival, I can hear annoying static noise(kind of buzz sound or "ssssss" sound) from the left side(around the key "A", "S", "Q", etc…) of the laptop. Here're the symptoms:

1. The static sound is noticeable and annoying when the laptop is connected with the original HP power adapter, same issue when the laptop is connected with 65W or 80W USB-C power adapters I have for testing, so the issue is NOT just a bad power adapter. As soon as the power cord is unplugged(that is, use battery power), the noise is gone;

2. Moving the touch pad or an external mouse makes the static noise louder, that is, when there is a mouse cursor move, the static sound goes up, and as soon as the cursor stops moving, the noise quiet a bit(but still noticeable in a quiet room). Hitting the buttons of the mouse doesn't increase the noise like moving the mouse, very strange.

3. The system is up-to-date or patched, also disabling audio from the O/S level didn't help. So I don't think it's a software related issue. And keep in mind that removing the power cord(doesn't matter the original HP adapter or the USB-C one) immediately remove all the noise, so it looks to be a hardware issue on the motherboard or the power supply component, somewhere in the left side.

4. About 6+ buyers who bought the same model of laptop(Pavilion 15z-eh000) in December complained on the forum about the same issue, while other buyers said no static noise heard, so this could be a QC problem. It was a deal during the holiday, so many buyers discussed this issue.

Please advise. Thank you for your help!

[alvinyun]

Does any one have suggestion for me? thanks!