HP DESIGNJET 500 stops mid print carriage jets for a few then acts if it printed complete print.

[leeriedesel]

Printer stop reandomly the cariage printheads stalls then acts if the print is done. Would a failing ink supply system to stop randomly finish with out printing the rest of print.

[Repairatrooper]

Does the plotter throw an error when it stalls. Head stalls are often caused by either a failing drive belt or lack of lubrication on the printhead carriage rod. Open the window and look closely at the belt, especially the far left and right sides, you will need a flashlight to see well. Any fraying or cracking of the belt indicates it is time to replace the carriage drive belt. If the belt looks ok, run your hand over the chrome rod that supports the print head. If it feels dry or gritty it needs to be cleaned and lubricated.

[leeriedesel]

Doesn't appear to have any fraying or worn out sections of the belt. I did get a new ISS as it was faulty from the Service utility test. This gave me great hope once the new ISS cleared up that test to pass. However what it prints out has gotten less than a couple of inches now. And now the troubleshoot service test cancels it self in first inch troubleshoot. Same with printhead alignment. 

[jprout65_es]

I have been dealing with this same exact issue for almost 2 years now.  Both myself and our outside IT consultant have had no remedies for this 'print stall' issue.  Strange thing is it will stop printing on one poster and the next poster in the print queue will print perfectly fine.

Also... I replaced all but the Magenta printhead and ran the print plotter image and it was not great.  So I cleaned and aligned the printheads 4 times and now it has a "Printhead Warning Error: Poor Print Quality" that will not clear itself but still prints.

Looking for solutions or steps taken that have solved this issue.