I have an old Calcomp 5536 that makes very nice plots, but lately It has been giving me service station errors. I think the pads on the service station have gotten so hard that the step motor in the service station can't push the pads against the heads any more. So, If you have an old Calcomp 5536 sitting around, I would like to buy the purge unit/ head service station out of it. I am willing to pay around 0 for the unit. please email me pictures of what you have if you are interested. Thanks, C. Alan