Set Input Signal Plus for an external streamer on Samsung TV
Identify the HDMI port your streamer uses, then enable the wider input signal range for that port and compare a known-good picture.
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Select the physical HDMI port
On a Samsung TV with Input Signal Plus, identify the port the streamer is plugged into before opening the settings. Samsung documents the option under External Device Manager on supported sets. Enable it for the intended input. For a box connected through a receiver, use the television port where the receiver sends its output. An app launched from the TV itself uses a separate playback path.
Keep a recovery format ready
Set the external box to a format that already gives you a picture. Enable the input setting, then test a known-good UHD item. If the screen goes blank when the box switches formats, return the box to the prior output using a working display or the box maker’s procedure. Test the same HDMI cable and input before adding a receiver to the chain. Write down which resolution and HDR setting triggered the loss of picture.