iMac 2017 – trouble with multi displays (DVI Dual, HDMI, HDMI)

Updated on 04-12-2019 in Adapters and Cables
1 on 03-12-2019

I purchased this adapter:

and I connect it to HP ZR2740w Display. Everything works fine. So I also have another monitor Samsung and LG TV. I wanted to connect them to my iMac as well. So I purchased also this adapter:

Which I wanted to use for my Samsung display and LG TV. 

And here comes problem. When I connect both monitors to dual hdmi monitor, only one displays is activated. But when I disconnect my HP ZR2740w monitor (on DVI interface) then both HDMI displays are active and show screen properly.

My question is: Is it even possible to connect 3 monitors (using USB-C = Thuderbolt 3 interface) at the same time?

And if not. Is there a way to say, which of 2 HDMI outputs are active?
For example: when i have connected Samsung and LG TV(to HDMI device) screen appears only on samsung. If I want to use LG TV I have to manually DISCONNECT Samsung. Which is bad, because I am affraid it can damage – cable / adapter – when i do it often.

Is there at least way how to tell the adapter to use only LEFT or ONLY right HDMI output? It simply does not detect both devices when HP is also connected.

Thanks a lot for advices.


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0 on 04-12-2019

Hello Pavel,

According to the Apple website it is only possible to connect 2 external displays, regardless the Imac 2017 21,5 inch or 27inch version. This effectively means the limitation is software driven. 

having said that it would make sense that the CSV-1574 does not do 2 screens on hdmi output when there is a screen connected to the CSV-1510 DVI. 

if you do find a work around be so kind to share it with us.

Best regards


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