DIAGNOSIS A blank control panel with no backlight indicates a failed control panel assembly or a loose internal cable connection, often from a previous jam clearance.
FIX 1. Unplug the printer for 2 minutes, then plug it back in. Listen for the usual startup sounds. 2. If the panel remains dead, you must check the internal LVDS cable. 3. Power off and unplug. 4. Open the rear access door and the top scanner assembly (lift the ADF). 5. Locate the thin, wide cable connecting the control panel to the main board. Reseat it firmly at both ends.
IF THAT DIDN'T WORK The control panel itself is likely faulty and needs replacement (HP part number LZ07A-10010).
HEADS UP Before disassembling, verify the printer is actually on by checking for a warm fuser or listening for fan noise. The screen is the only component that may have failed.