No output on TV, suspect GPU

porina · January 25, 2020

Still diagnosing this but this is what I have:

TV: LG OLED55B9PLA

It was working last weekend connected to a PC including a 2070. Fun playing WOWS in 4k. PC was left crunching for the week with TV off. Now I get "no input" on TV. I can VNC into the system and it is still running. nvidia driver still reports TV as connected. Tried changing HDMI cable. Tried different input on TV. Tried rebooted PC. Still TV reports no input.

Connect PS4 instead. Works fine.

Connect other PC with a 1070 in it, shows a desktop so that's progress. As an observation, the display only came up on the desktop. I didn't see the boot stuff, in case that might be a clue.

Given other devices work with the TV, the problem seems to be pointing towards the 2070 system. I need to connect that up to a monitor to check that still works.

porina · January 25, 2020

The 1070 system that looked so promising started glitching, then I got the dreaded "no input" from the TV.

Now I think I found the problem. It's the HDMI cable. Because I was looking at trying different devices, I had a few lying around. I tried each in turn. 2 of the 3 cables gave the same symptoms. Might work for a bit, then go "no signal". The 3rd one, worked fine right away. I'm leaving it on for longer to check it, but it is looking promising.

I guess since the PS4 was only outputting 1080p, it wasn't stressing the not so good cables. So, I guess I'll have to label the "good" cable for use with PCs, and the others are still ok for 1080p content.

porina · March 2, 2020

Minor update to this, I was using one of the cheap cables with the PS4 (FF7R demo just came out) and the screen blanked after about 10 minutes. I had ordered some certified HDMI cables but never got around to plugging them in. Swapped it over, fine for at least another 20 minutes.

This now leaves a new question, what could cause a cable to work initially but stop after some time? The only possible guess I have is temperature. On both the GPU and also the PS4, the area around the HDMI connector is exposed to hot air. Something could be marginal in the cable that gets pushed over by that extra heat.