Remedy: 1 Resetting the main power The print engine ROM checksum is faulty. Turn off the power switch and unplug the power cord. After 5s passes, reconnect the power cord and turn on the power switch. 2 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version. 3 Checking the EEPROM The EEPROM is not properly attached. Reattach the EEPROM. 4 Checking the engine PWB The connector and FFC are not connected properly or the wire, FFC or PWB is faulty. Clean the terminal of the connectors on the engine PWB, reconnect the connector of the wire, and reconnect the FFC terminal. If the wire or the FFC is faulty, repair or replace it. If not resolved, replace the engine PWB.