DIAGNOSIS This is almost always a failed low-voltage power supply (LVPS) board. A blank display with no status LEDs means primary power is good but the logic board isn't getting the right DC voltages.
FIX Unplug the printer for five minutes. Plug it directly into a known-good wall outlet, not a power strip. If the display remains dead, the LVPS needs replacement. This requires disassembly to access the board behind the right side cover.
IF THAT DIDN'T WORK Check the flat ribbon cable connection between the LVPS and the main logic board. A loose connector can cause the same symptom. Reseat it firmly.
HEADS UP Disconnect the power cord before opening any covers. The fuser unit stays dangerously hot for over 30 minutes after use.