Canon Community

My TR8620a started doing the following (shown in the attached photo) out of nowhere.  I've tried the following already...  Resetting it  replacing all ink cartridges  running every built-in maintenance process many times.    Any ideas? 

Can anyone help me understand what is happening with my yellow ink? On the Nozzle Check Pattern results exactly one-half of the yellow bar is not printing at all. I have cleaned and deep-cleaned countless times, reinstalled the print head, manually a...