Lines on a TV screen: test whether they follow the source

Record whether the lines are horizontal, vertical, fixed in one position, moving with the picture or visible only on a particular input. Also note whether they appear on menus, every channel or only one app. These observations are useful because a single screenshot cannot show whether the symptom follows the source or stays with the display.

• Lines on one HDMI device only: start with that source, cable and TV input.
• Lines on one channel or broadcast only: compare another channel and check the broadcast/provider signal.
• Lines visible across the TV menu and several inputs: run the built-in display test and contact the manufacturer if the test is affected.
• A cracked screen or physical impact: stop troubleshooting picture settings and ask the manufacturer about safe service options.

1. Run Picture Test or Screen Self-Diagnosis if your TV provides it, following the exact model’s support instructions.

   If the lines appear in the TV-generated test, the source cable is not the only place to investigate. Samsung recommends service when lines remain in its Picture Test.

   If that does not help: If the test looks normal, continue to the source/input branch; a clean test is useful evidence but does not guarantee every external path works.

2. If the test image is clean, switch between another built-in app and another input, then return to the affected source.

   If lines follow one external device, channel or app, troubleshoot that source and its connection rather than resetting the whole TV.

   If that does not help: If lines spread to menus or additional sources, rerun the test and share both results with the TV maker.

3. If the model has no Picture Test, use its official picture diagnostic or contact the manufacturer for the correct method.

   You avoid using a menu path that belongs to a different TV platform.

   If that does not help: If the symptom is persistent or worsening, stop changing settings and arrange support.

1. For an HDMI source, reseat the cable at both ends. If practical, try another input or a known-good cable, changing only one part at a time.

   If the line disappears after one change, the source path has been narrowed.

   If that does not help: If the Picture Test is clean but that device still produces lines through another input/cable, contact the source-device maker.

2. For an antenna or cable channel, compare other channels and check the service or signal before changing TV picture settings.

   If only one channel has the artifact, the TV may be displaying an issue already present in that signal.

   If that does not help: If multiple channels and TV menus show the same lines, return to the manufacturer’s diagnostic path.

A normal menu with an abnormal external picture is a clue, not proof that the TV is perfect. The TV test, another source and a cable/input swap each answer a different question; together they are more useful than replacing several parts blindly.

When lines appear in the manufacturer’s Picture Test or across the TV menu, the issue is no longer limited to one app or HDMI cable. Follow the manufacturer’s service instructions. Samsung notes that lines during its Picture Test warrant service and that physical screen damage may require repair; it does not recommend opening the set or swapping boards as a consumer troubleshooting step.

If the screen is physically cracked, tell the maker that before arranging service. Panel replacement can be costly and warranty coverage depends on the damage and terms; get a model-specific repair estimate before deciding what to do.

Provide the model code, a photo or video of the lines, whether they appear over the menu, the built-in test result, which sources were tried, and whether the symptom changes after switching inputs. Do not remove the TV back cover for a clearer picture. This evidence helps support assess the issue without an unsafe self-diagnosis.

• Problems with the picture on Samsung TV or projector — checked 2026-10-24
• How to troubleshoot TV picture and screen issues — checked 2026-10-24

Why do lines appear on my TV screen?

They may be part of one source’s signal, follow an HDMI connection, or appear in the television’s own display. Check the menu and built-in Picture Test to narrow the branch.

Can an HDMI cable cause lines on a TV?

A cable or source path can affect one external input. If lines appear in the TV’s own Picture Test or menu too, contact the TV maker rather than assuming a cable is the cause.

Are vertical lines on a TV always a broken panel?

A line pattern alone cannot identify the failed part. Use the TV’s manufacturer-provided test and service guidance; do not open the set or rely on an online board diagnosis.