Suddenly lost Yellow ? Roland VS300i

Roland VS-300i
I was printing just fine yesterday and had all colors . Today I go to print and I have zero yellow , Did a few cleanings and ran a few test prints , not a single spec of yellow . Took the ink cartridge out , shook it up , put it back in , few more cleanings and still no go . Removed the drain bottle , used a syringe and pulled a bunch of ink , again ,few cleanings / test print and zero yellow .

DX7 print head so priming only yellow ? No idea how I can do it .

any ideas ?
Also did a 20 min head soak , and doing another head soak as I type .

Thanks

 

Well good news ! I didn't even mess with the DAMPER. The damper is has 2 lines going to it so if it was that both inks would have an issue !!!!! So I ruled that out within 10 minutes of my issue .

I removed the YELLOW / CYAN line from the top of the DAMPER , plugged the CYAN .. this left me the Yellow line open only.

Tried suction with the yellow line and still nothing > Took a piece of copper welding wire ran it all the way up though the ink tube as far as I could > STILL nothing .

Took the other side of the printer apart , now I knew there was a blockage somewhere back there ... after diagnosing more I found a valve that I guess purges the ink ... It was stuck .

Took apart the valve and cleaned it good , primed the system from under the captop _ machine is PERFECT once again .

Called the local dealer just to get a good laugh , They wanted $1200.00 to come and fix it . I fixed it myself and didn't even need a new part .