Saving money on toner for the Lexmark e240 series
We discovered that Lexmark dosen't sell a 6000-page toner cartridge for the e240 series printers. I mistakenly bought one for an e330 (the vendor said it would work). The incorrect cartridge fits into the printer, but the '!' light on the front of the printer lit up and nothing would print.
I looked at the cartridge and discovered a small PC board with one chip and two contacts on the bottom of the case. "Aha!" I thought, "they're using the chip to ID the cartridge!" I put tape over the contacts of the cartridge that came with the printer. When I put it in, the printer reacted the same way, with the '!' light on and refusing to print.
I was able to gently pry the PC board off of the old and new cartridges. They're lightly glued on and the board material is strong, so there's not much worry about breaking them. I swapped the old for the new, and the printer is now happy with the 6000-page cartridge.
I replaced the $63, 2.5k page cartridge (2.52 cents/page) with a $95, 6k page (1.58 cents/page) cartridge (the 34015HA).