i have an hp deskjet 820cxi printer. its an oldie, but a goodie. whenever i do a "clean print cartridge", all 3 lights blink. i contacted hp and i have followed all of their procedures, but to no avail. i have 2 new cartridges inside. i have cleaned the contacts on the cradle using a damp q-tip. but still to no avail. any ideas? other than that the printing is fine, when the cartridges dont need cleaning. thanks, sk