Adjustments And Calibration; Internal Hard Drive - Xerox 7700DX - Phaser Color Laser Printer Service Manual

Adjustments and Calibration

The engine firmware has several built-in diagnostic routines that perform
various alignment and calibration procedures. The RegiCon 685 Adjustment
procedures should be used whenever the technician removes or replaces the
Laser Unit, the Print Cartridge Plate Assembly, the Mark-on-Belt Assembly,
Developer Housing Assembly or where color registration is bad.
The printer is shipped aligned, registered and calibrated. The major disruption
that can affect registration is when the NVRAM that contains the registration
parameters is cleared, requiring that registration be redone. For information
on resetting NVRAM see "Resetting NVRAM" on page 6-145.

Internal Hard Drive

The Phaser 7700 Printer has a standard hard drive installed in every printer.
The hard drive boots most of the firmware. There is a special file on the hard
drive that stores the specific calibration values for various sensors and for the
unique positioning of the laser in the printer.
During manufacturing, the calibration values from the engine NVRAM
have been written to the hard drive. The stored values can be written
back to the engine NVRAM by performing a front panel "Reset Engine
NVRAM Now" reset procedure.
If "resetting" engine NVRAM does not restore correct color
registration, the laser geometry has probably moved in the printer,
and the registration procedure must be performed. After completing
the registration process, perform the engine NVRAM "store" function
to store the new engine NVRAM values to the hard drive.
If the hard drive needs to be replaced, there is an engine NVRAM
"store" function in the service diagnostics that enables the current
engine NVRAM values to be written to the new hard drive.
If the engine control board is replaced, the NVRAM values on the
hard drive need to be restored to the new board with the engine
NVRAM "reset" function.
Phaser 7700 Color Laser Printer Service Manual 4-123