Dell 3000CN Color Problem Yellow is coming out greenish

I recently got a used Dell 3000CN printer that was not working right. I fixed the mechanical paper feed problem the unit had, but it still has a weird color problem.  The yellow comes out greenish.

When I got it the previous owner warned me about the weird color problem.  They said that at one point they ran out of one of the color toners, and the printer refused to print anything until the toner was replaced.  Since they did not have the correct toner on hand, and needed to print, someone in the office suggested putting in another color toner that they did have, to replace what they were out of.  They said that after they replaced the incorrect toner with a correct one it has done this.  I was not told what color they ran out of or what they replaced it with. 

When I got it the printer had all the correct toners, and said yellow was low.   When I saw this yellow comes out green I assumed it meant that they had subbed cyan for yellow, and still had some cyan toner in the works making the yellow come out greenish.  I removed the yellow toner cartridge, and carefully opened the 'door' on the printer where yellow toner goes in, and vacuumed out as much toner as I could, and reinstalled the yellow toner cartridge.  Still green.  I tried printing pages of nothing but yellow to pull the toner through the machine.  Now after about 50 pages of solid 100% yellow (greenish) it needs a yellow toner cartridge.  Since it had a yellow toner cartridge in it when I got it, that would suggest that it has used an entire yellow cartridge, and not cleared this problem.  I do not want to spend money on replacing the yellow toner on this printer if it will never recover and get the colors right again.  Could it have gotten some internal color calibration settings way out of whack when it had the wrong cartridge in it?  It went through a calibration when I first turned it on, so I would think that it should have fixed itself.  The cyan, magenta and black look fine in test prints.  

Any suggestions???