DesignJet, Large Format Printers & Digital Press

A few weeks ago my office purchased a designjet 500 from a friend of the owner.  I had already printed on this plotter before so we knew it worked well.  We set it up on our network and it printed with no problems for the first week or so.  Then about 2 weeks ago it started printing anything blue, a dark shade of blue, or grey in purple.  I am the only one in our office that uses the plotter as I am the only one using AutoCAD and no one else has need for it.  Therefore, I know I did not make any changes, and though it is on our network I am the only one that has access to it.

Now, as I mentioned this started happening a week or two ago.  Since our prints are internal use only I have been using spare time to attempt to find solutions to this issue.  I have searched this forum, and others and found various fixes, none of which worked.  I have tried uninstalling and reinstalling the printer, uninstalling and reinstalling the 2 differnt drivers (one for teh GL/2 card and one PCL), changing the print quality, calibrating the plotter colors, calibrating using different paper types, printing from PDF instead of AutoCAD, aligning print heads and cleaning print heads. None of this has worked.

One thing that I have seen in a few forums and on this Hp support page is updating the firmware, this i cannot do.  I was able to update the I/O firmware to the current version, but the firmware on the plotter is listed as Formatter firmware: A. 02. 05.  From a couple of forums I have read the firmware update A 02.08 and above fixed the color problem, however I can find no site from which to download the firmware, the HP download support center only has the drivers.  A couple of the forums, and the HP support page (linked above) have taken me to this site which, if you have looked at the support page i linked, is a completly different url than the one mentioned.

So, is there a fix to this? Is there a way to get the firmware update? Is there a different fix? As far as I can tell this plotter was built circa 2013(?) so I would thik it would still be supported, though it is out of warranty.  Any thoughts or insights would be greatly appreciated.  Also please forgive the book I wrote, i just did not want to get the "did you try searching the forum" response, or waste anyones time instructing me to do things I have already tried.

Thanks in advance for your help.