How to replace CN642A and CN643A HP printhead ?

Here are the steps to replace HP printhead CN642A  and CN643A:


Step 1:
Switch on the printer.
Open the cover and wait until the carriage stopped

Step 2:
remove all the cartridges

Step 3:
Unlock the printhead.

Remove the printhead

Step 4:
Clean the contacts on the carriage.

Step 5:
Install the new printhead

Lock down the printhead.

Step 6:
Install the new cartridges.
Close the cover