Canon BJC-820 Service Manual page 59

Part 4: TROUBLESHOOTING
8. ASF Sensor
Error
<Measure>
Visually check pick-up
roller
OK?
Yes
Check pick-up roller
operation
Does it function
correctly
No
Check pick-up roller
operation
OK?
Yes
Replace purge unit
<Cause>
Pick-up roller flag cannot be detected.
<Suspected parts>
• Is the pick-up roller's sensor flag broken or missing?
No
Replace pick-up roller
• Position the pick-up roller sensor flag so that it does not
cut off the light beam to the sensor.
Turn on the power and
check if pick-up roller operates correctly.
Yes
Replace logic board
• Remove ASF unit from main unit and
rotate the drive gear by hand to see if
pick-up roller and other parts operate
smoothly.
No
Replace ASF unit
4-8
ASF unit, logic board, purge unit.
BJC-8200