原帖由： Henry ,
Try removing all HDMI cables and then "remove" the power cord for about 10 minutes (powering off is not sufficient ). Then Plug in the power cord, then one HDMI cable and try your device that way. Also, something to note there is a known flaw with these tv's that cause a spike on the motherboard that cause the HDMI ports to stop working altogether. http://www.lg.com/us/tvs/lg-55UF6450-4k-uhd-led-tv Look under ratings and reviews. Hopefully the reset will get you backup and running though. The board replacement is not hard either though.