HP - Laserjet 2550 toner counter reset.

HP Laserjet 2550

Instruction:

1 Turn the printer off.

2 Press and hold the GO button (blue-green).

3 Turn the printer on and continue to hold the GO button (about 30 seconds).

4 After the Go, Ready, and Attention LED all turn on, continue holding until 
the Attention and Ready LED switch off (GO led still on).

5 Keep pressing the GO button AND now keep pressing the red button (about 15 seconds) until the 3 LED's stop blinking.

6 Release GO and red buttons. Reset is done.