Canon PIXMA MP750 Service Manual page 26

Symptom
Scanning The document does not
problems separate.
Faulty scanner unit's
sensors (The placed
document or
transported document is
not detected.)
The Nothing is printed.
Scanning
Image
Is
Abnormal
Solution
1) Check whether the
document feed motor is
driving all the rollers. (Check
for any damaged gears or
foreign matter stuck inside.)
(2) ) Cleaning the Separate
Rollor and RubberSheet. See
Chapter 4. Cleaning your
Machine.
(3) Replace the separation
roller ass'y and Upper guide
ass'y.
1) Check for any faulty
sensors while executing the
copying operation and test
mode.
(2) Check the connection from
Document sensor and
Document edge sensor to the
ADF board.
(3) Check the connection from
the ADF board to the sensor
board sub PCB (JADF1).
(4) Check the connection from
the sensor board (JADF1) and
SPCNT board.
(5) Replace the Document
sensor.
(6) Replace the ADF board
ass'y.
(7) Replace the SPCNT board
ass'y.
(1) Check the connection
between the contact sensor
and SPCNT board (JCCD1).
(2) Replace the SCANNER
unit.
(3) Replace the SPCNT board
ass'y.
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Remarks