Encountering a situation where your TV is not detecting HDMI input can be frustrating, but there are several troubleshooting steps you can take to identify and potentially resolve the issue. Here's a comprehensive guide:

• Check Physical Connections:   Ensure that the HDMI cable is securely connected to both the TV and the source device (such as a cable box, gaming console, or streaming device). If possible, try using a different HDMI cable to rule out cable issues.
• Test Different HDMI Ports:   If your TV has multiple HDMI ports, try connecting the device to a different port. It's possible that a specific HDMI port on the TV is faulty.
• Restart the TV and Source Device:   Power off both the TV and the source device. Disconnect the HDMI cable, wait for a few minutes, then reconnect the cable and power on the devices. This can help refresh the connection.
• Use Another Source Device:   Connect the HDMI cable to a different source device to see if the TV detects it. This helps determine whether the issue is with the original source device or the TV.
• Check Source Device Output Settings:   Ensure that the source device is set to output video and audio through the HDMI port. Access the settings menu on the source device and verify the display and audio output settings.
• Try Another HDMI Cable:   If available, use a different HDMI cable to connect the source device to the TV. Sometimes, a faulty cable can cause detection issues.
• Update Firmware/Software:   Check for firmware or software updates for both the TV and the source device. Manufacturers frequently release updates to address compatibility issues and improve performance.
• Perform a Power Cycle:   Unplug the TV and the source device from the power source. Wait for a few minutes, then plug them back in and power them on. This power cycle can sometimes resolve HDMI detection problems.
• Check HDMI-CEC Settings:   If your TV and source device support HDMI-CEC (Consumer Electronics Control), ensure that it is enabled. HDMI-CEC allows devices to control each other over HDMI, and disabling it might resolve compatibility issues.
• Try a Different Resolution:    On the source device, try changing the resolution settings to see if the TV detects the HDMI input. Some TVs may have limitations on supported resolutions.

By systematically going through these steps, you can identify and potentially resolve the issue of your TV not detecting HDMI input. If problems persist, professional assistance or contacting the TV manufacturer may be necessary.