Fix LG OLED "No Signal" and 4K HDR problems on HDMI ports
If your LG OLED suddenly drops to a black screen, it is usually a WebOS input quirk, Deep Color toggle, or a cable that cannot keep up with 4K HDR. This walkthrough is tuned for LG's HDMI layout (eARC on HDMI 2, 48 Gbps on all four ports on newer models) and the specific menu paths that tend to hide the right settings.
Quick checks to rule out simple issues
- Confirm the correct input
In Quick Settings, open the input list and make sure the device name you expect is actually on the active port. LG sometimes renames inputs when you change the icon. - Inspect the HDMI cable
Look for sharp bends, kinks, or loose connectors. Try reseating both ends until they click into place. - Test another HDMI source or display
If you can, plug a known-working device (like a streaming stick) into the same port, or plug your source into a different TV. This quickly tells you which side is misbehaving. - Restart everything
Power off the TV, the source device, and any receiver in between. Unplug them for 30 seconds before turning them back on.
Rebuild the HDMI connection step by step
- Start with a direct connection
If you normally run through a receiver or soundbar, temporarily connect the source straight to the TV with a short HDMI cable. This removes one variable while you troubleshoot. - Use the port that matches your feature
On most 2020–2024 OLEDs, HDMI 2 carries eARC and all four ports can do 4K120. If you only see issues on HDMI 1 or 3, move the cable to HDMI 2 or 4 and retest. - Enable or reset HDMI Deep Color
In Settings → General → External Devices → HDMI Input Format, toggle the active port to "4K" or "Enhanced." Turning it off and back on can refresh a stuck handshake. - Match resolution and refresh rate
Set the source to a conservative resolution first—try 4K at 60 Hz. Once you see a picture, step up to 120 Hz or VRR. - Power on in a clean order
Let WebOS boot to the home screen, then turn on the receiver (if used), and finally the source. Some LG sets cache EDID data differently depending on power order.
Expert tip: try a different HDMI cable, even if the old one “used to work”
Tip: A surprising number of no-signal problems end up being a marginal HDMI cable that only fails at 4K or at higher frame rates. Swapping to a short, certified Ultra High Speed HDMI cable is one of the fastest ways to tell whether you are chasing a wiring problem or a device issue.
Buy once for LG OLED HDMI stability
Scenario example
Scenario example: An Apple TV 4K is on HDMI 1 with Dolby Vision enabled. You see a black screen until you move it to HDMI 2 (eARC), toggle HDMI Deep Color off/on for that port, and set the Apple TV to 4K SDR with Match Range/Frame Rate. Once stable, turning Dolby Vision back on keeps the picture because the cable and port now agree on the full 48 Gbps link.
When to suspect the TV, source device, or receiver
- Source device problem – If the TV shows “No signal” no matter which port you try, but other devices work fine in the same port, the console or streamer may be at fault.
- TV problem – If multiple inputs intermittently lose signal for every device, check for a TV firmware update and consider a full factory reset after backing up your picture settings.
- Receiver or switch problem – If things only fail when a receiver or HDMI switch is in the chain, connect the source directly to the TV. If that works, review the receiver’s video pass‑through and 4K/8K settings.
If you still cannot get a picture
After verifying cables, ports, and basic resolution settings, persistent "No signal" or black-screen behavior usually points to a failing port or a deeper compatibility issue. Document which combinations of source, port, and cable work or fail. Having that matrix ready makes support with LG or your TV manufacturer far more effective and can help justify a warranty repair or replacement when simple fixes are exhausted.
If you want a brand-agnostic HDMI checklist, see our full HDMI “No signal” guide at /posts/4k-tv-receiver-hdmi-no-signal-checklist.