When the printer shows "Replace drum"or Drum end soon",please follow this video to reset your printer.
Part one：For Printer with Without Screen Display
First：Open the top cover of the machine
Second：Press and hold down the Go button for about 4 seconds until all the LEDs light up. Once all four LEDs are lit, release the Go button.
Last：Close the front cover.
Part two：For Printer with Multi-line LCD
First：Open the front cover
Second：Press Clear to reset the drum counter and Press the Up arrow key or 1 to reset the drum counter，When the LCD shows Accepted, close the front cover.