No video output if PC posts with HDMI plugged in

MatteRB26 · 14 Aug 2022 at 13:58

So I got a new monitor (https://www.samsung.com/uk/monitors/high-resolution/s80ua-27-inch-ips-uhd-4k-ls27a800unuxxu/ this one if it matters) last week and everything was great. However, the last couple of days my PC refuses to display output on either HDMI or DVI of the HDMI is plugged into my GPU (GTX 970).

So if I use just DVI, it will POST fine, plug in the HDMI for the Samsung and all is good.

If I have the HDMI in my GPU, either by itself or with the DVI, then my PC will POST and enter windows - which I know is happening because the SteelSeries software takes control of my RGB - but I don't get output on either HDMI or my DVI monitor, even if I unplug them and plug them in again.

If I unplug the HDMI from my GPU, hit the POST screen with the text then plug it in, there will be no issues.

I've tried other cables and both HDMI1.4 and 2.0 modes with the same symptoms.

I've tried leaving the HDMI in the GPU but disconnected from the monitor and it does the same thing.

I'm at a total loss as my PC itself is booting fine, but doesn't seem to display any video unless I unplug the HDMI before POST. Any more avenues to try...? Or does it sound like my GPU is just on the brink?

arknor · 14 Aug 2022 at 18:56

try the firmware updater tool

it's meant to fix display port issues though not HDMI

NVIDIA Graphics Firmware Update Tool for DisplayPort 1.3 and 1.4 Displays

Download English (U.S.) drivers for NVIDIA hardware - , , ,

www.nvidia.com

t31os · 14 Aug 2022 at 19:30

You could try setting the input on the monitor to HDMI (presumably it will be on auto by default) and see if that helps.

BUDFORCE · 15 Aug 2022 at 14:19

arknor said:
try the firmware updater tool

it's meant to fix display port issues though not HDMI

NVIDIA Graphics Firmware Update Tool for DisplayPort 1.3 and 1.4 Displays

Download English (U.S.) drivers for NVIDIA hardware - , , ,

www.nvidia.com

Probably be this.

MatteRB26 · 16 Aug 2022 at 08:07

My GPU already has custom firmware on it for higher clocks, wouldn't the firmware update trash that?

It's also been using DVI & HDMI for many years in the past with a previous monitor. I try turning the monitor on and setting it to HDMI but it goes into standby before my PC even hits the POST screen.

I'm using DP on the new monitor now and that seems to be working just fine with DP & DVI.

I think I'll get the other monitor back out and plug that into the HDMI and see what happens as it was always fine before...

MatteRB26 · 16 Aug 2022 at 19:22

Okay so I've discovered that the old LG monitor works fine on the HDMI port on my GPU still, only the Samsung via HDMI causes any trouble.

So I can roll with:
DisplayPort > Samsung
HDMI > LG
DVI > BenQ

I don't know what's up with the Samsung HDMI causing my GPU to refuse any output, but this seems to work...