Canon CLBR 460ps Service Manual page 330

CHAPTER 4
3. Memory Read mode
The adjust-values (15 items in the shaded area of Table 4-9-1) stored in the DC controller EEP-
ROM (NVRAM) for back up are read into the video controller RAM.
Video controller PCB
RAM
EEPROM
a. Memory Read mode operation procedures
1) In the Service mode, press the MENU key to display "READ ENGINE NVRAM" in the message
area and then press the ENTER key.
2) Use the up and down arrow keys to select "YES" or "NO" ("YES" to read the memory) and
then press the ENTER key.
3) Returns to "READ ENGINE NVRAM" when the adjust-values were read into the RAM on the
video controller correctly. "READ MEM ERROR" appears when the values were not read cor-
rectly. In such a case, turn OFF the power and then turn the power back ON in the Service
mode. Then, perform 1) and 2) again.
4. Memory Write mode
The adjust-values (15 items in the shaded area of Table 4-9-1) read into the video controller RAM
for back up are confirmed or modified and then written into the DC controller EEPROM (NVRAM)
and video controller EEPROM (NVRAM).
Video controller PCB
RAM
EEPROM
a. Memory Write mode operation procedures
1) In the Service mode, press the MENU key to display "WRITE ENGINE NVRAM" in the mes-
sage area and then press the ENTER key.
2) Modify the adjust-values of the 15 items, which were read into the RAM in the Memory Read
mode. Use the up and down arrow keys to change value and press the ENTER key to go to
the next item.
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Write
Figure 4-9-4
Write Write
Figure 4-9-5
DC controller PCB
EEPROM
DC controller PCB
EEPROM