Hoping someone can offer assistance on a graphics issue

[barc]

I thought I'd try this here before venturing out to the wider webz:

My desktop is connected to a LG 4K TV via hdmi. The graphics card is set for 3840 × 2160 and it's always been just a little overscanned on all 4 sides. Other than that, it's always worked fine (a little less than 2 years).

So yesterday, I decided to do a custom config via NVDIA graphics desktop to get rid of the overscan. Things worked good until I turned the TV off and then back on again a little later (I left the PC on). The TV will no longer recognize the PC input.

I've reseeded the graphic card (GTX 4090). I've hooked the PC up to a separate PC monitor (using the same hdmi cable), and it works. I've connected the PC to the TV via the PC's built in Intel graphics and it works. I've connected another PC up to the input on the LG TV and it works.

My research said to update to the latest drivers for the 4090, so I did. No effect.

Any suggestions on what I might try next? I can render a complex scene in a few minutes with the NVDIA card that takes almost an hour with the built in Intel card :0

[bricks]

TV input is fine, the cable is fine, and the GPU hardware is fine.
The only remaining culprit is the custom resolution / timing override stored in the NVIDIA driver.

Most likely fix: Reset all custom resolutions
Even if you deleted the custom resolution, NVIDIA may still be applying modified timing parameters behind the scenes.

Do this:

Open NVIDIA Control Panel

Go to Display → Change Resolution

Click Customize…

Uncheck “Enable resolutions not exposed by the display”

Delete every custom resolution listed

Apply

Reboot the PC

Power on the TV after Windows is fully loaded

If the TV still doesn’t detect the signal:

Next fix: Force-clean the NVIDIA EDID cache
Windows and NVIDIA both store EDID overrides. Clearing them resets the handshake.

Method A — Clean reinstall NVIDIA drivers
Use DDU (Display Driver Uninstaller) in Safe Mode:

Remove NVIDIA drivers completely

Reboot

Install the latest driver fresh

Reconnect the TV

This wipes any corrupted timing overrides.

Method B — Remove EDID overrides manually
If you prefer not to use DDU:

Open Device Manager

Expand Monitors

Right-click your LG TV → Uninstall device

Check Delete the driver software for this device

Reboot

This forces Windows to rebuild the EDID profile.

LG-specific fix: Turn off “HDMI Deep Color”
Some LG TVs reject custom timing when Deep Color is enabled.

On the TV:

Settings → General → HDMI Ultra HD Deep Color → Turn OFF for that HDMI port

Power-cycle the TV

Try the 4090 again

If none of the above works
Try these signal-level resets:

1. Change the 4090’s output port
Sometimes one port retains corrupted timing data.

2. Force a different refresh rate
Try 30 Hz or 60 Hz at 3840×2160.

3. Use a different HDMI input on the TV
Even if another PC works, the EDID handshake may differ per port.

4. Try DisplayPort → HDMI active adapter
This forces a fresh EDID negotiation.

[barc]

@strangebricks, that did it. I've come to the unfortunate conclusion that I need a better TV. I had my 4090 set to 3840x2060 and the TV simply can't process it. I can't live with 1920x1080. And I still have the fricking overscan that I started out trying to fix. This TV is about 5 years old, so I guess I'll go try and find something better. Thanks for the assist. I sent you some points.

[bricks]

Glad that helped. Appreciate the points. If you can hold out until black Friday TV's are always a deal.

[Ethiopia]

I'll likely never encounter this but am saving the fix anyway....
...ya know? Just in case.
Thanks!

[Josie]

It is a very good tip for sure. Any time I have problems like described, DDU is the way to go.

[barc]

Luckily, I had a spare Samsung that we never opened from a BF sale a couple of years ago (was supposed to go with my kid to college, but they said it was too big for the room). I set that up and it's working great. I've got full UHD resolution and no overscanning now with it. And from what I'm reading about LG spying on us to the level of creepy-as-f, I'm no longer going to be getting LG in the future. Thanks again.

[CKAY]

what model is your TV sometimes there are hidden service menus that can help with overscan

[barc]

No worries @creepuk. I've already replaced the TV with one that I had sitting around unused and still in the box. The old one is now sitting in the basement waiting to go to the dump. It's too old and too heavy to keep around. It did have 4 hmdi ports tho, which was nice.

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