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LG TV HDMI No Signal – Meaning, Causes & Fix

LGSmart TVUpdated 2026-10-14

A "No Signal" message on an LG TV HDMI input appears when the TV is set to an HDMI input but isn't receiving a valid video signal from the connected source device. The TV has switched to the correct HDMI input and is actively listening on that port, but the source device (a cable box, streaming stick, game console, Blu-ray player, or computer) either isn't powered on, isn't outputting a signal, or has a connection issue between the source and the TV. This guide explains what causes an LG TV to show No Signal on an HDMI input and how to diagnose and fix the connection. For related LG TV issues, see our LG TV Memory Full Message guide and our Samsung TV Red Standby Light Blinking guide.

Quick Answer

What it means

The TV is set to an HDMI input but isn't receiving a valid video signal from the connected source device — the source is off, not outputting a signal, or has a cable or port issue.

Severity

Low

Can you fix it yourself?

Yes — most No Signal causes (source power, cable, input selection, source settings) are resolved by the homeowner without tools.

Call a technician when

A technician is rarely needed — contact LG support only if No Signal persists across multiple known-good source devices and cables, which may indicate a failed HDMI port on the TV requiring service.

What Does HDMI No Signal Mean?

An LG TV displays a "No Signal" (or "No Signal Detected") message on an HDMI input when the TV is tuned to that input but receives no active video signal. The TV's HDMI inputs are always listening; when no signal is detected, the TV shows the No Signal overlay after a few seconds and may eventually power off the panel to save energy (the screen goes dark but the TV stays on).

Importantly, a No Signal message means the TV is working correctly — it's the source device, the cable, or the source's settings that are at fault. The TV is doing its job: listening on the selected input and reporting that nothing is coming through.

Common causes include:

1. Source device is off or in standby: The cable box, streaming device, game console, or computer is powered off or in standby and isn't outputting a signal — the most common cause. 2. Wrong HDMI input selected: The TV is set to HDMI 1 but the device is connected to HDMI 2 — a simple input-mismatch. 3. Faulty or loose HDMI cable: The HDMI cable is loose, damaged, or poorly seated at either the TV or the source end. 4. Wrong source output resolution or mode: The source device is outputting a resolution or refresh rate the TV doesn't support, or is outputting to a different display (a computer in extended-desktop mode, for example). 5. Source device sleep or HDCP handshake failure: The source went to sleep, or an HDCP (copy protection) handshake between the source and the TV failed, blocking the signal. 6. Failed HDMI port on the TV: A specific HDMI port on the TV has failed (a hardware fault) — less common, and typically only affects one port while others work. 7. Failed HDMI output on the source device: The source device's HDMI output has failed — testable by trying the source on another TV. 8. HDMI cable too long or low quality: A very long or poor-quality HDMI cable degrades the signal below the detection threshold.

This signal-detection issue is a display-input problem, distinct from the power-board Samsung red standby light blinking fault, which prevents the TV from powering on at all.

What Causes This Error?

  • Source device is off or in standby and isn't outputting a signal — the most common cause
  • Wrong HDMI input selected on the TV — the TV is set to HDMI 1 but the device is connected to HDMI 2
  • Faulty or loose HDMI cable that's loose, damaged, or poorly seated at either the TV or the source end
  • Wrong source output resolution or refresh rate the TV doesn't support, or the source outputting to a different display
  • Source device sleep or HDCP handshake failure blocking the signal
  • Failed HDMI port on the TV — a hardware fault affecting one specific port
  • Failed HDMI output on the source device — testable by trying the source on another TV
  • HDMI cable too long or low quality degrading the signal below the detection threshold

How to Fix HDMI No Signal

  1. 1

    Confirm the source device is powered on. Check that the cable box, streaming device, game console, or computer is fully powered on (not in standby or sleep). A powered-off source is the most common cause — press the source's power button and wait a few seconds for it to output a signal.

  2. 2

    Confirm the TV is set to the correct HDMI input. Press the Input (or Home) button on the LG remote, scroll to the input list, and select the HDMI port the source is physically connected to (HDMI 1, HDMI 2, HDMI 3, etc.). A common mismatch is setting HDMI 1 when the device is on HDMI 2.

  3. 3

    Reseat or replace the HDMI cable. Unplug the HDMI cable at both the TV and the source, inspect the connectors for damage, and reseat them firmly. If the message persists, swap in a known-good HDMI cable — a faulty cable is a very common cause and is quick to rule out.

  4. 4

    Try a different HDMI port on the TV. Move the HDMI cable to a different HDMI port on the TV and select that input. If the signal appears on the new port, the original HDMI port on the TV has likely failed (a hardware fault) — the other ports remain usable.

  5. 5

    Try the source device on a different TV. Connect the source device to another TV with the same cable. If the source shows No Signal on the other TV too, the source device's HDMI output has failed — the issue is the source, not the LG TV. If the source works on the other TV, the issue is the LG TV's port or a cable incompatibility.

  6. 6

    Check the source device's output resolution and display settings. On a computer, set the display output to the LG TV at a supported resolution (e.g., 1920x1080 at 60Hz). On a game console or streaming device, check the video output settings and set them to Auto or a standard resolution. An unsupported resolution can trigger No Signal even with a good cable.

When to Call a Professional

An HDMI No Signal message rarely requires a technician — it's resolved by confirming the source is on, selecting the correct input, reseating or replacing the cable, and trying a different port. Contact LG support or a TV repair professional only if No Signal persists on a specific HDMI port across multiple known-good source devices and cables (confirming the port has failed), while other HDMI ports on the same TV work. A failed HDMI port is typically a main-board fault and may require main-board replacement ($200-$450 including parts and labor), though using a different port is usually the practical workaround.

Can You Still Use the Device?

An LG TV showing No Signal on an HDMI input is fully functional — the TV itself is working correctly; it's simply not receiving a signal on the selected input. You can switch to other HDMI inputs, use built-in streaming apps, or watch over-the-air channels while you diagnose the No Signal issue on the affected input. The TV only becomes unusable for that specific source until the source, cable, or input issue is resolved.

Official Resources

Disclaimer: This article is for informational purposes only and does not constitute professional repair advice. CodeExplain is not affiliated with LG or any other brand mentioned. Always consult a qualified technician for complex repairs.