Chosen Solution
Hi all! A couple of months ago I upgrades my iMac 2017, 21,5” model with a SSD and RAM. It worked perfect. I was running BigSur. After the BigSur update from 11.0 to 11.1 I’m hearing a buzzing noise. I first I tought it was the fan, but I dont think so. I installed ‘Macs Fan control’ and turn down the speed. The noise didn’t go away/decrease. When I decrease the screen brightness to almost 0 then the noise is almost gone. What could it be? Thanks! Update (03/04/2021) Hi all, I didn’t repair the Mac. All functions were working, noise didn’t get louder so I went with it. After working on the Mac I shut it down and after 45 minutes I want to start working again…The Mac did not start up. Nothing, no noise, connection, screen. Also disconnected power cord. What to do? Replacement of PSU?
It sounds like a power supply issue or
What you are hearing is a coil hum/whine. Your system has transformers and inductor coils which can become loose in their cases so they vibrate. It has nothing to do with the macOS release your system has on it. You’ll need to open the system up and carefully try to narrow down where the sound is coming from so you can isolate out the part that will need either replacement or repair.
