Chosen Solution
My Thunderbolt Display recently began making a buzzzing noise. The buzzing starts soon after it’s plugged into my MacBook Pro 2019 ( but not immediately) then after about 3 minuets (sometimes longer) the lights in my room begin to flicker. As soon as I disconnect it from my computer, and the screen goes blank, the buzzing stops and the lights stop flickering. I’ve tried plunging the Display directly into the wall, vs the power strip, into different wall receptacles, and into different ports on my laptop, no change. Also, this did start after updating my laptop to macOS 11 Big Sur. Lastly, I’m running three 27” Thunderbolt Displays and this is only happening to one of them. Thank you in advance. Update (11/17/2020) After doing some reading, I’d like to add, decreasing the screen brightness lowers the noise and I’m not using the Display to charge my MacBook and there is nothing else plugged into the Display via USB etc…
I think you are facing a power issue within your buildings wiring! You’ll need to get a AC outlet tester 3-Wire Receptacle Tester here’s more on why A MUST HAVE TOOL - The Electrical Outlet Tester - How to use and why you should have it I’m suspecting you have a hot ground! The other possibility is the Thunderbolt display power supply has a short to ground.
