I have a xerox 7428 with error 124-315 how can i fixit

The serial no., product no., and billing count are stored at three locations; the MCU NVM PWB (IOT), the SEEP ROM (SYS1) on the Backplane (BP) PWB, and the ESS NVM PWB (SYS2). This procedure allows the data in all three locations to be synchronized in case of replacement of one of the PWBs, or due to data corruption associated with one of the following faults:

• 124-324 (3 Billing Counter Mismatch)
  124-325 (1 Billing Counter Mismatch; Unable to recover Billing Counter during recovery)
  124-312 (Product No. Mismatch)
  124-313 (Serial No. Mismatch)
  124-310 (Product No. Failure: Not initialized)
• 124-311 (Serial No. Failure: Not initialized)

1. Enter UI Diagnostic mode ( Accessing UI Diagnostics).
   Select Adjustment/Others.
   Select Machine ID/Billing Data Settings.
   Select a PWB with the correct data.
   Select Start.
2. Enter the correct serial number in the Serial Number screen and then select Confirm.