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All these cartridge chips are the same, they’re just a memory chip on a I2C bus.
4 connections – power, ground, SDA (data) and SCLK (clock).
If you put a logic analyser on there you’d see the printer read the chip to get the current number of pages, and write back an updated count after printing. All the chip resetters do is restore the chip to the ‘factory’ setting, ie zero pages.
In theory what you do is put in a new cartridge, and record what the printer writes to the chip. When you refill the cartridge you write that data to the chip, thus resetting it. Something like an Arduino can do I2C.
Easier said than done, the manufacturers have wised up and encrypt the data and so on. Not like in the old days where you could just cut a track, or where HP used to store the page count in a text file on your PC.
Tony
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
Sent: Saturday, 5 November 2016 12:19 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: RE: [Homebrew_PCBs] Re: Pantum 2500 hack to direct print toner rolling date back and page counts
Hi All,
I've taken apart a couple of these printers for this purpose. There is no obvious battery (coin cell, etc) on the main logic board or the digital board. There are lines from the digital board to the cart labeled sda sclk, along with what I would guess is a ground, and a connection that appears to not be connected.
Best,
-Ozz