Canon LBP-800 Service Manual page 95

The CPU detects the following failures and error by monitoring /BDI sent from the BD sen-
sor, and reports it to the interface controller.
1) Scanner failure
The CPU assesses a scanner failure when the /BDI cycle does not reach the specified value
within 3.5 seconds after the completion of the initial forced acceleration.
2) BD failure
The CPU assesses a BD failure when the /BDI is not detected within 0.1 seconds after com-
pletion of scanner motor forced acceleration or when the detected /BDI cycle is not equal to
the specified value for 2 continuous seconds or more after the scanner has become ready.
3) BD error
The CPU assesses a BD error when the /BDI is not detected at the specified cycle while the
/BD is output to the interface controller from the engine controller.
The CPU does not report the BD error to the interface controller if a door open is detected
within 0.2 seconds after detection of the BD error.
The CPU cancels the BD error when a scanner failure or BD failure is detected after detec-
tion of the BD error.
CHAPTER 2
2 - 21