Cracking noises cannot be fixed with software.
05,004.44 is related to a drum motor, and the clicking noises must mean a gear is slipping when it turns, cause is unknown but a service tech is needed.
21,000.60 means the firmware on the printer is not the one that goes to the model you have, which would imply a failed Altboot was done, or a forced upgrade altboot with the wrong firmware was done. This should not have been caused by a simple NVRAM reset. But no matter the cause, it is again, likely to require a technician. Neither code relates to each other at all.
The number you have at the end of each code is too greatly varied, it signifies the page count of the device when the fault occurs, so even if you are missing a digit in code 2, they still happened
120,517 impressions and 12596 impressions = 107,921 pages
120,517 impressions and 120596 impressions = 79 pages
xerox 8560 MFP started making loud cracking noises.
tried reset NVRAM to no effect.
power cycling has no effect.
tried to connect to another computer and it does not even detect.
please help. thank you