GTX 970 - no signal HDMI - Sierra 10.12

[cyruxx]

Hello,

I've recently installed MacOS Sierra 12.2 and my HMDI port no longer sends signal to the 2nd monitor(TV) - or so it looks like since the display is seen in the Display settings and when i click outside the screen (where my 2nd monitor should be), the menu bar fades out but my TV says "No Signal".



I didn't inject Intel or Nvidia driver and I'm using iMac 17,1 as system definition.

Note: The HDMI cable/port has no problem since it worked on Windows and MacOS 10.11 without any issue.
Attached is my config.plist.

Let me know if any more info is needed since it would make my life easier to be able to use my TV as a 2nd monitor.

 

[hpsychedelic]

Your problem seems similar to mine and we're rocking similar hardware sans the MoBo.

I didn't inject Intel or Nvidia driver and I'm using iMac 17,1 as system definition.

17,1 has been known to cause issues so you may wanna either try 14,2 and see if that works, in which case you can try any of the troubleshooting in the sticky topic, specifically, you need to use the AGDPFixv1.3 or the PixelClockPatchv2 maybe.

Let me know if any more info is needed since it would make my life easier to be able to use my TV as a 2nd monitor.

What TV are you using? Mine is a Samsung KU6300 and I had to disable UHD color on HDMI_Port_1 for it to work (will try a DP adapter next and allegedly I should get 4k@60Hz no sweat).

 

[cyruxx]

What TV are you using? Mine is a Samsung KU6300 and I had to disable UHD color on HDMI_Port_1 for it to work

Thank you for suggesting that, seems like this fixed the problem, i've disabled UHD colour for that HDMI port and the image is now displayed.
However, now i'm facing another issue: the TV (Samsung HU6900) screen turns black then the image comes back, kind of like a "refresh".

I've changed the definition to 14,2 but it seems like it got a bit worse since the "refresh" is more frequent.

I've applied the AGDPFixv1.3 before "fixing" the 1st issue and now I've applied the PixelClockPatchv2 however the issue still persists.
Might this be the issue? Can this be reverted somehow or should i go for a clean install to see if that's the problem?

Note: I tried scaling the TV to multiple resolutions but with no avail.
Note2: In the meantime I've updated to 10.12.2 but still occurs.

Any idea/suggestion on how to fix this?