Power On Self-Diagnostic Test - Xerox 1235DT - Phaser Color Solid Ink Printer Service Manual

Power on self-diagnostic test

Initial test. The following checks are automatically performed when the printer is
powered on:
1.
ROM check (loader). Checks ROM by comparing the sum of bits in the
received data unit by the number of bits in the transferred data unit.
2.
Flash ROM check. Checks Flash ROM by writing a present data pattern in
Flash ROM, reading the contents of Flash ROM, and comparing the data
read from Flash ROM by the data written in Flash ROM.
3. RAM check. Checks RAM by writing a preset data pattern in RAM, reading
the contents of RAM, and comparing the data read from RAM by the data
written in RAM.
4.
EEPROM check. Checks ID numbers stored in the fixed addresses of
EEPROM. Checks the content of the menu area by control firmware and the
engine area by engine firmware.
5. Mechanical check.
All the engine fans are turned on and also checked to ensure they run
properly.
The fuser heaters are activated to heat up the heated rollers.
The print engine checks to see that the imaging drum units are installed.
The engine motors are rotated to ensure that their rotation sensors are
detected.
A sensor check is made to determine if any paper is jammed in the
printer.
The print engine checks the presence of each toner cartridge.
Option unit check. Checks whether the optional units (such as the paper
tray 2, paper tray 3, duplex unit) have been installed before entering the
operation mode.
The print engine performs a color misalignment detection check by
laying down patches of toner on the transfer belt and reading their
relative positions to each other with the color registration sensor
assembly.
After the fuser reaches its idle temperature the printer is placed on line in
its READY state.
The print engine is initialized. If the startup page feature has not been disabled
and no error occurred with the printer, the printer prints a startup page
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