Canon LBP1760P, Service Manual

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D. Self Test
The printer has the function to check the condition of the video controller by executing the self
diagnosis program of the video controller. This is called "self-test". Self-test has two kinds of
test; power ON self test and power ON key sequence.
1. Power ON self test
The power ON self test is executed following the procedures stated below every time the printer
is switched ON.
1) Tests all DRAMs on the video controller. "Service call" is displayed on the LCD if any error
occurred.
2) Tests all program ROM, font ROM, and option ROM. "Service call" is displayed to LCD if any
error occurred.
3) Tests inside of the CPU. "Service call" is displayed on the LCD if any error occurred.
4) Ends the self-test. The error is displayed on the operation panel if it is notified from the
engine controller.
5) After the completion of the self-test, "READY" message is displayed on the operation panel,
then PCL demo-page is printed automatically.
2. Power ON key sequence
By pressing the specified keys simultaneously when turning the power switch ON, the specific
function can be executed. Only the "Cold Reset" sequence stated below is for user.
a. Cold Reset
Turn the power switch ON while pressing the GO key (PPG Check Sum) or GO and Value keys
simultaneously (PS Check Sum).
This function resets all the printer settings to the factory default settings.
b. Check Sum Functions
Turn the power switch ON while pressing the GO and Shift keys simultaneously.
The printer performs the check sum on the requested ROM bank with this function. The cal-
culated Check Sum is displayed on the LCD.
c. Factory Reset Function (A4/LTR)
To reset the paper size default to A4, turn the power switch ON while pressing the Menu, Item,
and Value keys simultaneously.
To reset the paper size default to Letter, turn the power switch ON while pressing the Item,
Value, and Enter keys simultaneously.
The printer sets the default to the selected paper size (A4/LTR) with the function, resets the
page count to zero, and then executes the "Cold Reset". Future Cold Resets retain the paper size
default selected here.
d. Panel Check Function
The printer executes the operation panel diagnosis and the test sequence with the panel check
function. The Function has following sequences.
1) The printer is powered ON with Go and Enter keys both pressed, causing the "PANEL
CHECK" message to be displayed on the LCD.
2) Steps 3 through 8 below may be invoked in any order and/or multiple times.
3) If the Go key is pressed, the OnLine LED is lit and the "OPERATION CHECK" message is dis-
played. Releasing the key clears the LED and the message.
4) If the Shift key is pressed, the Job LED is lit and the "OPERATION CHECK" message is dis-
played. Releasing the key clears the LED and the message.
5) If the Menu key is pressed, the Alarm LED is lit and the "OPERATION CHECK" message is
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CHAPTER 2