Canon ImageRunner iR8500 Series, Service Manual, Page: 217 / 1122

Chapter 4
4-7
4.3.3 Start-Up Sequence(iR105)
0006-9777
iR105
When the main power switch is turned on, the CPU on the main controller PCB first executes the self-diagnosis program stored in the boot ROM.
The self-diagnosis program checks the condition of the SDRAM and the HDD; if a fault is found, it will indicate an error code in the control panel.
F-4-8
ERRO CODE:
E601-0000, -0001
Indicates an error in image transfer data.
E602-0001, -0002
Indicates a write/read error.
When the self-diagnosis ends normally, the boot program stored in the boot ROM starts up to read the system software from the HDD to write to the system
area of the SDRAM.
When the write operation ends, the system software in the SDRAM starts up to initialize the components of the machine (at the end of which the normal
operating screen will appear in the control panel) and, at the same time, the LED lamp of the Start key will change from red to green to indicate that the
machine is ready to accept a job.
The system software of the machine consists of multiple modules, and specific modules as needed at specific times are called into the system area of the
SDRAM for execution.
Self-
diagnosis
program
Boot
program
Boot ROM
CPU
SD RAM
System
area
Image data
area
Main controller PCB
HDD
Access to the program at time of execution