designjet 500ps rescue (repair)

I inherited a HP Designjet 500PS. It has earlier in it's life a magenta printhead explosion... so was a mess inside (nobody bothered to properly disassemble and clean the printer.... Did that, including disassembly and reassmbly of the service station. However, yellow stopped working... so it can't align print heads.... so I picked to primed tubes... but that needs a set of setup printheads that I don't have.... and I can't get out of that step even with a power cycle.... couldn't try to 'clean' the heads either.... as it needs to align the heads first ... which fails as yellow is not printing.... so I've gotten myself into a realy catch 22 situation with it.... And now I'm stuck w/o setup print heads. So, does anyone have or know where to cheaply get a set of setup printheads for a designjet 500, 500PS, 800, or 800PS (should all be the same). A replacement ink tube spare part would have the carts as well. This is the 25" variety, but other than the spare ink tube kit being different for 25" vs 42", the setup printheads would all be the same. Anyone have a service station... this one fails sometimes when it tries to ratchet the big wheel on the left side of the service station... Could also use a set of print heads. Thanks, -- Curt