4K picture (50p/60p) from an external device is not displayed.

If the following types of picture are not being displayed on the TV from an external device, use a High Speed HDMI cable with the 4K logo.

• 4K (24, 25, 30Hz) YCbCr 4:4:4 / 8bit
• 4K (50, 60Hz) YCbCr 4:2:0 / 8bit

If you want to view the following types of picture on the TV from an external device, use a High Speed HDMI cable with 18 Gbps of bandwidth.

• 4K (50, 60Hz) YCbCr 4:4:4 / 8bit
• 4K (50, 60Hz) YCbCr 4:2:2 / 8bit
• 4K (50, 60Hz) YCbCr 4:2:0 / 10bit
• 4K(50, 60Hz): YCbCr 4:2:2 / 10bit
• 4K(50, 60Hz): YCbCr 4:2:2 / 12bit
• RGB signal

• In addition, update the TV’s software to the latest version, and then change the HDMI signal format setting. Operate as follows to set the HDMI signal format.

• 1. Press the HOME button on the remote control.
  2. Select Settings.
  3. Select External Inputs in the TV category.
  4. Select HDMI Signal format and set to Enhanced format.

• NOTE : If the signal is in enhanced format, picture or sound from a portion of external devices that do not support 4K may not be output normally. In such cases, change the signal format to standard format or switch the HDMI cable to an input for signals in standard format.

For details on which video formats are supported by your TV, refer to the following FAQ.
Types of 4K (50p/60p) video signals supported by the TV