If the standard simulation codes do not work, or if you are facing a persistent "Call for Service" code (like an H4 or H5 error, which denote fuser or laser unit issues), the standard user reset may be locked. In this scenario, you access the deeper service mode.
He backed out to the main prompt and entered . This was the "Clear All Trouble" command. It was the "nuclear option" for errors that didn't go away with a simple power cycle. He pressed Start , and the machine let out a long, low whirring sound—the sound of a brain being scrubbed clean. Chapter 4: The Rebirth how to reset sharp ar-6020