Causes of high frequency noise

I am using POP2. I always plug it in, wait a while, and I can hear the high-frequency noise. High-frequency noise continues to occur as long as power is supplied. Is the noise only coming from my equipment because there is a problem with my equipment? If not, is it the noise of the piezo motor mounted on POP2? The noise seems similar to that of a piezo.

Hi Lee,
Sorry for the inconvenience.Can you record a video for the noise you mentioned for the scanner for us to check? You can send us the video to Thank you!

OK, I will send the video to customer service.