Separating a working scanner from its broken printer

April 11, 2012 By Leave a Comment

The laser printer portion of this all-in-one machine gave up the ghost and [Entropia] couldn’t get it working again. But the scanner was still functioning so he decided to separate the scanner from its dead printer module.

The model in question is a Samsung SCX-4200. The design is actually perfect for separation because the scanner sits on top of the out feed tray of the printer. It can even be lifted to allow more room for printed pages to pile up. All he has to do is separate the hinged connector and reroute the flat cables. But the real question in [Entropia’s] mind was whether or not the control board would work without the laser printer components connected to it.

He carefully disassembled the unit, spilling toner here and there which is left over from a catastrophic knock-off toner cartridge incident. A quick test showed him that although the drivers complain that the paper tray is open, the scanner does still work. He glued the controller board seen on the left to the bottom of the scanner enclosure, and added some felt feet. Now his scanner is closer to the size you’d expect. And on the plus side he gained a geared stepper motor, laser scanning unit, exhaust fan, and a couple of solenoids to use in future projects.

Filed Under: peripherals hacks, repair hacks Tagged With: , , ,

Resetting the page count on a laser printer

March 5, 2012 By Leave a Comment

[Brian] really liked his Samsung color laser printer right up until it was time to replace the toner cartridges. A full set of toner cartridges sell for about the same price as the printer itself, so [Brian] figured he could simply refill the toner in the cartridges he already has. The printer sends out the ‘low toner’ warning  based on page count and won’t print if the page count is too high, negating the economy of a toner refill kit. Luckily, [Brian] figured out a dead simple way to reset the page count so he can use those third-party refill kits.

All the configuration settings and page counts for the printer are stored on an I2C EEPROM. After dumping the data held on this EEPROM with an Arduino and sniffing everything going into the EEPROM with a Bus Pirate, [Brian] was nearly at his wit’s end. Thankfully, serendipity intervened. When [Brian] restarted the printer with the Bus Pirate attached, he noticed it took much longer to initialize. Printing a configuration report, he was trilled to see that all page counts have been zeroed.

The final hack that allows [Brian] to reset the page count and used refilled toner cartridges is a simple wire that ties the SDA line of the EEPROM to ground on boot. [Brian] used a momentary switch, but given this is a once-every-few-months operation, a simple wire would suffice. Check out [Brian]’s page reset demo after the break.

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Filed Under: hardware, peripherals hacks Tagged With: , , ,