Fix your printer !

Try to reset the H code : Press CLEAR, EXPOSURE MODE, CLEAR, EXPOSURE MODE. The display should go blank. Then enter 14 with the copy count keys and press START. If the machine does not turn off and back on by itself - then turn it Off and back on. See if the H code comes back. Xerox 6R915 Toner for XD-120f 13R551: Drum unit Xerox

4,0XX.6x Process Control Software Fault Solution 1 : a. Reset NVRAM and then retest. b. Ensure ground integrity for the system. c. Replace the EEPROM chip. d. Reboot the system. 1. From the System Setup menu, go to Information --> Troubleshooting --> Service Tools menu. 2. With the cursor at the top of the Service Tools menu, press both the Up Arrow and Down Arrow buttons to display the Hidden Service menu. 3. Reset NVRAM is in there Solution 2 : 1. Turn the system power ON. 2. Wait for the Xerox logo to begin moving across the display. 3. Before the logo is centered on the display, press and hold the Back and Info buttons on the control panel. 4. Hold both buttons until the display reads “Beginning Service Mode Initialization”. Release the buttons and the system reboots into service mode with the Service Diagnostics menu displayed.

31,004.40:6909 : it's a mechanical initialization jam error. Pull out the paper tray to make sure it doesn't have a jam. Try also to manually feed some heavy paper or card stock through the printer to make sure the sensor in the preheater isn't stuck. 39,002.40 : DRAM test failure. 39,012.40:56208 : "Cycle the power" and if that does not work replace the document feeder. 39,012.41 : Document Feeder Optical Failure. Replace the document feeder. 4,0XX.6x: Process Control Software Fault. Reset NVRAM and then retest. Ensure ground integrity for the system Replace the EEPROM chip. Reboot the system. From the System Setup menu, go to "Information", "Troubleshooting" Service Tools menu. With the cursor at the top of the Service Tools menu, press both the Up Arrow and Down Arrow buttons to display the Hidden Service menu. Reset NVRAM is in there.