4k TV won't display anything from my PC

Associate
Joined
11 Jan 2011
Posts
2,285
Merry Christmas Eve everyone!

I'm trying to simply connect my PC upstairs to my TV downstairs. The TV is Sony X900F. I'm using a HDMI cable from the 3070 HDMI port to the HDMI port on my TV.

This worked fine a few weeks ago but ever since I've upgraded my PC it hasn't.

The TV is HDR.

No matter what combination of display settings, refresh rates, scaling or most other settings the TV just simply does not display anything from my PC. It is driving me mad having spent about an hour already on this.

Could you please help me! Thank you
 
Your TV will be expecting VESA signal timings, so in essence the graphics card should be set to replicate what might come from a 1080p source (1920 x 1080 pixels) at 50Hz or 59.95Hz.

If you're trying to send UHD/4K res then you'll be out of luck. You'll struggle with that at 5m so 20m is well out of question.

The simplest option is to bring the PC to.the TV whilst setting up using a short HDMI cable. Once up and running then you can take the PC back to its remote location. If it still works then you're good to go. If it doesn't then you know that the long HDMI cable is an issue.
 
It worked before when I had a 2080. I upgraded my PC and now this has happened. I was able to have 4k, 60hz and HDR working with the cable before the upgrade so it can't be the cable.

I have managed to get it to display but only when I change the HDMI signal format setting to "standard" on the TV, but this results in a fuzzy picture with off colours and I cannot change the Output colour format to anything other than YCBCR420.

Really confused to be honest! I need it to work with the "enchanced" HDMI signal format somehow.
 
It worked before when I had a 2080. I upgraded my PC and now this has happened. I was able to have 4k, 60hz and HDR working with the cable before the upgrade so it can't be the cable.


Unless you installed an active amplified cable or an optical cable then I would question whether what you think you were sending was what was actually what was going through the bit of wire.

Thousands of UK home cinema users face exactly the same problem of getting full bandwidth UHD HDR signals to their new UHD projectors via anything much longer than a 5m copper cable. It's just too much data for High Speed copper cables to handle.

This is an extract from the CEDIA advice on UHD bandwidths:


HDMI products supporting up to 9Gbps (maybe stated as 10.2Gbps High Speed) can support up to 4K/30 HDR with 4:2:0 or 4:2:2 only.


HDMI products supporting up to 18Gbps (those advertised as "4K/60 4:4:4") can also only support 4K/60 HDR with 4:2:0 or 4:2:2 only.


Here is the link to the full article

https://community.cedia.net/blogs/david-meyer/2018/05/16/hdmi-data-rates-for-4k-hdr


To summarise what they're saying, if you're trying to send a desktop screen or console image with 60hz refresh and UHD resolution and the higher bitrate required for HDR to a display device using ordinary High Speed copper cable rated at the standard 10.2Gbit/s then you're shot out of luck. It will need 18Gbit/s to do that.



You can either reduce the frame rate, or sack the HDR feature (reduce the colour depth), but yer cannae change the laws of physics.
 
Last edited:
I understand this but how does that explain the fact that I was able to enable HDR, 10 bit, 4k, 60hz when using the same cable from my PC to the TV before? It definitely worked.

Now it doesn't. Although after further research some people have had this same issue after the latest update for the TV, so I think that may be the issue. Bit annoyed as you cannot rollback TV updates!

The cable is definitely 18Gbps. I don't have another 4k HDR display to test it on but if it is the TV update then that's a pain in the arse!

Would a shorter cable such as 10M paired with some kind of HDMI repeater/booster work?
 
Well, if it is truly 18Gbps then it should work.

Are you trying to send RGB (4:4:4) down the cable? Have you tried Component ((4:2:2 or 4:2:0)?

I don't get those options in Nvidia control panel. I think they only appear if the HDMI Enchantment mode is set on the TV but if I do that there is no signal at all from the PC
 
For that length of cable I had to use a HDMI repeater otherwise the signal would cut out at random or not display at all.

The one i picked up was only £20 neoteck was the brand works fine now.
 
I ordered three new cables and tested them all. 2 of them worked fine. No idea why the original cable stopped working all of a sudden but oh well at least it's solved.

Thankfully I can return the original cable. The two that worked have a chipset device mid way through the cable, about 5M in. should have ordered this kind of cable originally!

Thank you all for the help!
 
Back
Top Bottom