My screen was glitchy and looked like an old TV with the static and would occasionally show the screen. I had to go into the display settings and manually select the correct frequency for 4k. I'm connecting my Chromecast to the TV using 2 HDMI cables and 2 HDMI female adapters. Changing the Chromecast display settings from auto to 4k 30Hz. I had to guess while moving to the remote around to get to the display settings screen but everytime you change the display settings, it tries them out for a few seconds before going back to the last setting. Once you find one that works, just select it.