I followed Walker's advice on loosening up on the buffer assembly. It required three attempts before I found the sweet spot referred to by Walker. I had issues producing a clean nozzle check pattern; I ran 12-15 head cleanings from the printer interspersed with the pzo/paper towel cleanings. The nozzle check patterns changed with each head cleaning, which led me to believe things were coming around under the hood. I'm now able to resume printing without those PK runs all over my paper. For any junior member contemplating the replacement of their ink supply unit, my suggestion is to go for it. Buy the manual from 2manuals.com, print it in color. Buy the parts from Compass Micro. Knowing what you'll be dealing with will prevent you from going down one of several rabbit holes in the manual. The process is definitely rather simple, provided you're patient and have nimble fingers. And remember to gently snug down on the buffer assembly.
Thanks, Dana and thanks, Walker