TV picture too dark
When a TV set is its on own setting, the picture looks great. After TV input is switched to HDMI that is connected to X1 box, the picture becomes darker, even the brightness setting is highest. Troubleshooting shows that the setting changed to 1 or 2 or 3, brightness never changes! There is only 3 levels of brightness. Is that right? What's wrong with it? How can I troubleshoot or fix it?