Monday, 31 December 2018

Resetting the Page Count on a Samsung Laserjet (MLT-R116 Drum)

Our Samsung M2835 printer's drum unit (MLT-R116, not toner, the drum unit) finally hit its software-programmed end-of-life of 10,000 pages.  This is annoying for several reasons:

  • Page 9,999 was perfectly fine
  • I disagree with business practices involving software-enforced obsolescence 
  • Other printers (Brother and HP) provide an option to reset the page count
After some research, it turns out drum unit uses the same technique as toner cartridges to enforce end-of-life.  It uses a small 4Kbit i2c EEPROM to store the page count.  

There are some great resources for resetting almost the same EEPROM on toner cartridges on Samsung printers.  I used and adapted these to reset the drum counter.

Here's the Chip with contacts soldered to it so I can plug it into my raspberry Pi.





And here's the chip by itself:





And here's the connection to the RPI:



So once connected, dumping and re-writing the ROM is easy.  Use the above links to enable i2c on the RPI and then:

  • python speer.py -b 0x50.bin --addr 0x50
  • python speer.py -b 0x51.bin --addr 0x51
  • bvi 0x50.bin
    • Change offset 0x0C to 00 00 00 00
  • python speer.py -r 0x50.bin --addr 0x50
Now the drum counter reports 0 and the printer will print again.  Note: from what I have been reading, some versions of the firmware require modifications to other offsets too.  It's probably easiest to take a snapshot of the eeprom, save it somewhere safe, and then reload the eeprom 5 years later when the page counter is too high.