You'd think that the only thing I do around here is save instructions on how to reset printers.
Here's how you reset a Brother HL-2240D, with TN-420 or TN-450 toner cartridges.
- Turn the printer off.
- Open the front toner/drum cover.
- Press and hold the Go button while turning on the printer.
- Release the Go button after the Toner, Drum, and Error LEDs turn on, with the Ready LED off.
- At this point, all LED lights should be off.
- Press the Go button 2 times.
- The Toner, Drum, and Error LEDs will turn on.
- Press the Go button:
- 6 times for TN-420 cartridges.
- 7 times for TN-450 cartridges.
- At this point, the Error LED will start to flash.
- Close the front cover.
- Restart the printer.
These instructions were first found on 123inkcartridges, on Wednesday, September 13, 2017. I copied them here so I had access to them in case it ever left the web.