My Officejet Pro 8500A Plus stopped printing. I recently replaced the black ink with authentic HP ink. The Self Test diagnostic page prints in magenta and says that everything is ok for all colors of inlk- ink cartridge status, printhead status.
I uninstalled and re-installed the drivers. I did cleaned printheads 10 times. The magenta, orange and yellow print but not the black. The black cartridge is full. My unit is out of warranty.