Complete GS6000 black ink dropout. Any ideas?

[IvanDD]

Was getting a bit of smudging on the black nozzle checks, so we did a head wash and lost all black ink. There seemed to be air in the lines but that has cycled out. We went from having no black at all to a little here and there. I can do head cleanings through the menu and sometimes the black will look better than the picture below, and sometimes worse. There doesnt seem to be any rhyme or reason to it.

I'm about to have a tech out to replace the head... is there anything you guys would suggest first?

 

[Maxime]

Hey Ivan, having a most part clogged back here. Do you know if I can head-wash it with just one cleaning cartridge? The system allows for single head washing but warns about having "cartridge 's' " ready. Don't want to get stuck mid way..

cheers
Max