Default Serial Number found in the main and backup NVM. It seems that both the Print Mech PCA and Hard Disk Drive have been replaced together.
Try the following:
1. Perform the “Error 71:19 Recovery” Service Utility.
You MUST NEVER replace both the Formatter and the PrintMech PCA at the same time. If both parts need to be replaced, you MUST first replace one part and then power ON the Printer until it completely initializes. Then you can power OFF the Printer and replace the other part.