Hello everyone, I'm the owner of an imac late 2013. For months now I have found that the screen emits strange noises, crackles. The whole is accentuated when you lower the brightness. I sent the mac in assistance and after 5 days it was returned with the same problem .. Do you have any advice ???
Thanks so much
iMac (27-inch, Late 2013), iOS 9.2.1
Hi there lucaeconomia,
Welcome to Apple Support Communities.
From what I gather, you sent your iMac in for service because of an unusual noise issue which is persisting even after receiving your Mac back from service. The article below may help you resolve the issue, as it provides information and troubleshooting tips that assist in identifying location-specific audio issues caused by ground loops.
Macintosh: Solutions for noise in the audio signal - Apple Support
Take care.
imac crackles
