After many years of service I have trouble with a DesignJet 5000. It may help others (myself included) to describe some stuff here.
Model: C6090A Error: Check printpath (2) Solution: Replace belt Why? Because people at the HP fora suggest it and there are lots of rubber particles in the printer.
Google on HP partserver and you'll never find it (HP, wake up). So go directly to http://partsurfer.hp.com/ . Now somehow HP sites are often slow and after plenty of time outs it's tempting to Google on part http://www.google.com/search?q=Q1251-60320 and buy it somewhere else. HP really screwed me with four standard hard drives for two printers but in this case trying to buy directly from HP results in a reasonable price which is a good thing for the perception of HP on consumer level. More later