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Figured out how to change brightness on thunderbolt display! You have to have both USB and Thunderbolt cables plugged in.

If you only have thunderbolt cable plugged, it will be at max brightness and unchangeable.

Earlier displays & monitors

Posted on Oct 17, 2023 2:56 PM

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Posted on Oct 17, 2023 6:28 PM

The Thunderbolt Display does not have a USB cable, only Thunderbolt and MagSafe. You must have the similar looking LED Display, which has Mini DisplayPort, USB, and MagSafe. A Mini DisplayPort plug will work in a Thunderbolt 2 socket (but not in a Thunderbolt adapter).


The LED Display's needs it's USB cable connected for its brightness control and rear USB ports to work.

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Oct 17, 2023 6:28 PM in response to bos_borgor

The Thunderbolt Display does not have a USB cable, only Thunderbolt and MagSafe. You must have the similar looking LED Display, which has Mini DisplayPort, USB, and MagSafe. A Mini DisplayPort plug will work in a Thunderbolt 2 socket (but not in a Thunderbolt adapter).


The LED Display's needs it's USB cable connected for its brightness control and rear USB ports to work.

Oct 21, 2023 1:39 AM in response to bos_borgor

How to tell these displays apart:


  • 27" LED Cinema Display – which requires Mini DisplayPort input – has model number A1316. It has three USB 2.0 ports, but no FireWire 800 or Gigabit Ethernet ports.
  • 27" Thunderbolt Display – which requires Thunderbolt input – has model number A1407. It has the three USB 2.0 ports, plus a FireWire 800 port and a Gigabit Ethernet port.


Figured out how to change brightness on thunderbolt display! You have to have both USB and Thunderbolt cables plugged in.

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