I am up against a wall with this problem. Last Nov my hp1100 which had performed excellently for 3 years stopped printing red. Installing new cartridge, cleaning, buying brand new hp cartridge instead of recycled - everything failed. In despair bought new model, same machine different number, hp 1200. After only 6 months this is exhibiting the same problem but with the black cartridge. As I kept the 1100 I tried swapping over the printhead (these are located in a different section from the cartridges) and - for a time - it worked, then back to zilch. I swapped the printheads back. I did not buy this from a shop, I bought on ebay, but it was from a computer company, brand new (printheads, cartridges still in wrappers). I have written them outlining the problem but they have not replied, This must be a common problem with this printer, but I need help in solving it as I am out of ideas. Can anyone help?
Geraldine