We have several old but reliable HP 4100 printers. They are work horses and generally easy to fix/get parts for when needed. This situation is a bit different. So the basic problem is I go to print a 12 page B&W text report to Printer C and I get 3 prompt pages and then the printer while still running says processing. It will do this forever until you stop it. You can open the front hatch which stop it from running, let it sit 5 seconds, shut the door (let it do it's thing) and then you will get about 3 more pages. Rinse and repeat.
Doing a little reading online I read it might be your Firmware module, Ram, Jet Direct Card, or Fuser. So I do some swapping of all of those with our spare printer. I even swapped toner for the hell of it. NO difference.
Next I try the backup printer, put the jet direct card of Printer C into the Backup and...