You did not connect this with Thunderbolt 2. You connected it with mini DisplayPort. Same connector. Different signals.
The Cintiq 27QHD touch uses DisplayPort for the display connection and USB for the peripheral connections.
The Apple Thunderbolt 3 to Thunderbolt 2 Adapter does not pass DisplayPort signals. It is only for Thunderbolt devices.
The iMac has Thunderbolt 3 ports which can also output USB, DisplayPort, and HDMI. You need a USB-C (DisplayPort alt mode) to DisplayPort cable or USB-C to DisplayPort adapter.
- Answered by Joseph V from Fort Langley
- Flag as inappropriate Answer (Can i connect a wacom cintiq with this adapter to a new iMac ? I used to connect my Wacom cintiq 27 hd touch, with a thunderbolt 2 to my old iMac)