There could be several reasons why the screen on your Hisense-Roku TV appears to be dark. Here are some possible explanations:
Incorrect Picture Settings: Your TV's picture settings might be set to a low brightness level, or the backlight settings may be set to a low level. You can adjust these settings by accessing your TV's menu settings and adjusting the picture settings accordingly.
Room Lighting: If the room you are watching TV in is too bright or too dark, it can affect how the picture appears on your TV. Adjusting the room lighting can help to improve the picture quality.
Faulty Connections: Check all the cables and connections between your TV and any external devices you are using (such as a cable box, gaming console, or streaming device). Loose or damaged cables can affect the quality of the picture.
Hardware Issues: There might be an issue with the hardware of your TV, such as a faulty backlight or power supply. If none of the above solutions work, you may need to contact a technician or the manufacturer for assistance.