Hi Watcher, Thank you for your feedback regarding the screen abnormalities you're seeing on your TV. To help determine if the issue is related to the panel itself, we recommend starting with a Picture Test, which displays a high-definition image you can examine for flaws: Settings > Support > Device Care > Self Diagnosis > Picture Test If the issue appears during the test and across all sources (built-in apps, HDMI devices, etc.), it may indicate a panel-related concern. You can also try displaying solid-color test videos (red, green, blue, black, white) from a USB drive or YouTube. This can help you identify whether any pixels are stuck or not functioning properly. In some cases, unplugging the TV for a few minutes and rebooting it can help resolve stuck pixels caused by temporary display behavior. If the problem persists after these steps, the TV may require service. To set up a service appointment, please contact Samsung Support at 1-800-SAMSUNG, 8AM – 12AM EST, 7 days a week. LiveChat and additional support resources are also available through the Support link on our website. ~ Samsung Advisor

Hi Bonbon, Thank you for sharing your experience with Samsung’s U7900F. If your TV is displaying lines on the screen, we recommend the following steps to help isolate the issue: 1. Check all input cable connections for any external devices (e.g., HDMI, streaming boxes, Blu-ray players) 2. Switch channels or inputs to see if the issue appears across all sources 3. Run a Picture Test to check for panel-related issues: Settings > Support > Device Care > Self Diagnosis > Picture Test 4. Perform a cold boot by holding the power button on your remote for about 10 seconds 5. Ensure your TV has the latest software installed: Settings > Support > Software Update If the issue continues after these steps, the TV may require service. For further assistance, please contact Samsung Support at 1-800-SAMSUNG, 8AM – 9PM EST Mon – Fri, 8AM – 6PM Sat – Sun. LiveChat and additional support resources are also available through the Support link on our website. ~ Samsung Advisor