If the display screen is black; please confirm the following:
1. Is the Display powered on? Check that the power cord is plugged into a working power outlet.
Is the power LED next to the power button on the Optoma display lit? Typical standby mode power LED is red. Try turning off the Display from the Optoma remote or hold down the power button. If necessary, and the display is still not responsive, please unplug the power cord for 5 minutes and plug power cord back in. A normal Optoma display power bootup sequence will show the Optoma logo on the screen, then it will show your normal Optoma display home screen.
2. If there is power to your display and your screen is black, is there a source like a laptop plugged into the HDMI port of the Optoma display? Are you playing a YouTube Video or video file on the display in full screen? If so, restart the video, or close the video player and try playing the video again. Please note that if you are streaming a video online or trying to access an internet page like YouTube; please ensure your Optoma display is on a wired or wireless network that supports internet. If your internet is down at your site; then you will not be able to access the video or play the video from the internet site.
3. If the video you are trying to play from the video player is not playing, try a different source to the Optoma display. If another video source works (i.e. via HDMI cable connection like a Blu Ray player, or External Media player) then it means your Optoma display is working fine; and the issue may be due to your original source video player not being compatible. Please reach out to Optoma Technical support if you need further assistance if you've done the troubleshooting recommended here and still continue to have issues. Optoma Support may guide you to do a reset or a FW update if one is necessary for your situation or will determine if your unit qualifies for an RMA.