Hi!
Finally I am able to print and recognized that after switching to the 2nd+ layer the cooling fans start and they are making extreme noise. I canceled my first prints as I thought this is an error beeping from the mainboard but found out (by coincidence) that these are "just" the cooling fans. I checked that and when running at 100% you can of course hear them clearly but the beeping is gone. As soon as they run at lower speeds (about 250 of 255) you hear that beeping like noise.
Any thoughts on this?
As Dataris mentioned loosening the bolts will help but there will always be some noise at lower RPM (fist few layers). If it's that much of a concern you could plug just one of the fans directly into the board and power to 100% on second layer in Cura for PLA printing. Currently with both fans it will defaulting to 60% power with PLA.
Didn't work for me...
I'd brought up a similar issue last week. For me the fans were making the noise because the bolts were too tight, so they couldn't actually start spinning at low RPMs. Try loosening the bolts for the blower fans slightly and see if the noise lessens. In my case I could actually see the fan not spinning at all until about 35%, but the noise would go away if I gave the fan a light push to start it spinning.