About a month ago, my beloved Thunderbolt display began buzzing. After some research, it seemed that there could be all sorts of solutions. The one that seemed to almost always work was sending off the monitor to get the power supply fixed.
Apparently, there’s an issue with the power supply that can be confirmed if you crank up the display brightness. I cranked up my brightness and sure enough the sound was louder.
The buzzing didn’t start, however, until I was on my computer for a while (20-30 mins?) so each day when I came in, the silence would offer me some dim hope that maybe it fixed itself.
I figured that if it was quiet at first, the reason it began buzzing was because it got too hot. If I could lessen the burden placed on the power supply, and thus reduce the heat, it should stop. I recently started powering an old Macbook Pro with my cable (tho the display displays what’s on my Mac mini). To solve the buzzing, I stopped using my Thunderbolt display to power my laptop. That reduced the heat and there’s no more buzzing.
Note that this worked, then it didn’t for like a day or two, but then it did again for good. Now, my Thunderbolt Display hasn’t buzzed for a full week. Let’s hope it keeps going. I love this thing and I’m totally distraught that Apple discontinued Thunderbolt production.
I’d suggest that, in general, people don’t use the built-in power cable if possible as it seems to lessen the lifespan of older power supplies. I didn’t have this issue until I powered that laptop for a couple months straight :(