It's possible the backlight has failed. All LCD TVs require some sort of backlight, since the LCD panel itself emits no light. Plasma and OLED do emit light, so they don't have backlights. If you can see a faint image on the TV screen after it's turned on, that tends to point to a failed backlight. You can contact Hisense to see what their warranty coverage is on your set, and if it's no longer covered you can find out an estimated repair cost.
Dan
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