I have a VS-640 running CMYKx2. Everything was printing fine yesterday until I noticed all of a sudden my colors looked very dull. I did a nozzle test and one of the black cartridges only had 1 nozzle firing. I then did a manual cleaning and got about 60% of the nozzles to fire. Then I did a normal cleaning and ended up with more drop out with back down to about 40% firing. I did some research and arrived at the conclusion that there must be air in the line (the cartridge that wasn't firing had just started giving a low ink warning in Versaworks). My research told me that a Choke Cleaning would purge the system of any air. I ran the choke clean and opened and closed the valves as instructed by the printer and the end result was the horrible nozzle test. I'm assuming something in the Choke Cleaning must have caused the issue but I'm not sure. I've since replaced the ink cartridge, changed all consumables (wiper, felt, cap top) with the same end result test print. Any suggestions on my next step? Consumables were replaced after the Choke Cleaning so could it be possible that one of them may have caused a back Choke Cleaning? I don't have any experience with changing dampers and I don't have any replacements here but would that be something that would cause this? Thanks for any help you can give.