External displays with iMacs 2020 does not work

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Level 1

8 points

External displays with iMacs 2020 does not work

Hello,

I have problem with external displays with iMacs.

Until now, I've used 2x iMacs and external Eizo displays connected to them (via Thunderbolt / DVI adapter) and everything worked fine.

iMac 2011 27’ (MacOS High Sierra) ––> Thunderbolt 2 / DVI ––> EIZO CG 211

iMac 2011 27’ (MacOS High Sierra) ––> Thunderbolt 2 / DVI ––> EIZO S2410W

I upgraded the computers to the iMac 2020 and connected these same external monitors via Thunderbolt 3 (Thunderbolt 3 / DVI reduction) and the monitors don't work. They flash at regular intervals (an image appears there) and immediately go out again.

I tried to change reductions, displays and cables, but with the same result. It seems to me like a problem for iMacs.

Does anyone have any recommendations?

Use

iMac 2020 27’ (MacOS Big Sur) ––> Thunderbolt 3 / DVI ––> EIZO CG 211

iMac 2020 27’ (MacOS Big Sur) ––> Thunderbolt 3 / DVI ––> EIZO S2410W

CableMatters Thunderbolt 3 / DVI reducer

Thanks

Simon

iMac Line (2012 and Later)

Posted on Oct 9, 2021 3:40 PM

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Answer 1

Best reply

simbla Author

Level 1

8 points

Oct 16, 2021 12:33 AM in response to simbla

Solved!

In the end, I managed to solve the problem by trial and error. In both my configurations, the active adapter works https://www.club-3d.com/en/detail/2525/usb3.2_gen1_type_c_to_dual_link_dvi_d_hdcp_off_version_active_adapter_m-f_for_apple_cinema_displays/ with the HDCP OFF function. There is an adapter in the version with the HDCP ON function, but the monitors do not work for me - they flash.

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Answer 2

a brody

Level 10

83,299 points

Oct 9, 2021 3:52 PM in response to simbla

DVI is an older digital technology that has been replaced by Displayport and HDMI. Do these monitors have either? You'll find many more good Displayport and HDMI to USB-C adapters. My two favorite are:

https://www.smklink.com/products/usb-c-multi-port-hub

and

https://www.siig.com/catalogsearch/result/?q=JU-DK0F11-S1

You may find a DVI adapter to USB-C from either of these companies will work better. One thing about USB-C video adapters, they need power from the USB-C adapter for a laptop, or a source of their own 100W power to work properly.

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Answer 3

simbla Author

Level 1

8 points

Oct 10, 2021 1:03 AM in response to a brody

This path is not real. Both monitors have only DVI ports, no HDMI.

I used a reduction from Cable Matters (the only one I found) to connect - https://www.amazon.com/Cable-Matters-Adapter-USB-C-White/dp/B01N78S0OT

I also tried to work around it and use the tried and tested reduction from older iMacs Thunderbolt 2 to DVI - Thunderbolt 3 / Thunderbolt 2 ––> Thunderbolt 2 / DVI. But that doesn't work at all. The monitor is not even detected in the system preferences.

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Answer 4

simbla Author

Level 1

8 points

Oct 13, 2021 2:30 PM in response to a brody

I don't think this reduction will work either. In the discussion with this product, it is mentioned that the adapter does not work with older DVI monitors, such as the Apple Cinema Display, etc., which require dual DVI. It will probably be the same problem as my broken connection via the Cable Matters adapter.

Does anyone have a tip for a Thunderbolt 3 / DVI adapter with dual-link DVI, which has 6 TMDS channels? The problem is written here: https://kb.cablematters.com/index.php?View=entry&EntryID=109

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