The Scanner Fails To Move Forward; The Scanner Fails To Move In Reverse - Canon NP6251 Service Manual

CHAPTER 11 TROUBLESHOOTING

39. The scanner fails to move forward.

Cause Step
Cable 1
Scanner path 2
Scanner motor 3
(M3)
DC controller
PCB

40. The scanner fails to move in reverse.

Cause Step
1
DC controller 2
PCB
Scanner motor
(M3)
11-108
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Checks
Is the scanner drive cable routed
correctly?
Is the scanner rail free of dirt?
Does the scanner move smoothly
when pushed by hand?
Set the meter to the 12VDC
range, and connect the probes of
the meter to the terminals shown.
Does the voltage change when
the Copy Start key is pressed?
+ –
M3ON J112B-6 J112B-3 about 0 to 5 V
M3F/R J112B-7 J112B-3
about 5 to 0 V
Checks
Does the scanner move forward?
Set the meter to the 12 VDC
range. Does the voltage between
J112B-7 (+) and J112B-3 (–) on
the scanner controller PCB
change to about 5 V when the
scanner stops moving forward?
CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
YES/NO
NO Route the cable
correctly.
NO Is the surface of the
scanner rail soiled? Is
there foreign object that
comes into contact with
the scanner. As
necessary, clean,
lubricate, or correct.
Reference:
YES Replace the scanner.
motor.
NO Check the wiring from
the DC controller PCB to
the scanner motor; if
normal, replace the DC
Voltage
controller
about 0 to
YES/NO
NO See "The scanner fails
to move forward."
NO Replace the DC
controller PCB.
YES Check the wiring from
the DC controller PCB to
the scanner motor; if
normal, replace the
scanner motor.
Action
If the surface of the rail
is soiled, clean it with
alcohol, and apply a
small amount of
lubricant.
Action