Canon NP6621 Service Handbook page 77

22 The registration roller fails to operate.
Cause Step
Registration 1 Press the Copy Start key. Does the
roller registration roller rotate for about 1 sec
immediately after the scanner starts to
move forward?
DC control- 2 Set the meter to the 30 VDC range.
ler PCB does the voltage between J312A-5 (+)
and J312A-6 (–) on the DC controller
CL1 (regis- PCB change from about 0 V to about
tration 24 V?
clutch)
23 The scanning lamp fails to turn ON.
Cause Step
Scanning 1 Turn OFF the power switch, and
lamp disconnect the power plug. Is the lamp
installed correctly?
Scanning 2 Have the ends of the scanning lamp
lamp blackened?
Dc controller 3 Replace the DC controller PCB. Is the
PCB problem corrected?
Composite
power
supply PCB
Checks
Checks
TROUBLESHOOTING MALFUNCTIONS
Yes/No Remedy
YES Check the drive assembly of
the registration roller.
NO Replace the DC controller
PCB.
YES Check the wiring from the
DC controller PCB to CL1; if
normal, replace CL1.
Yes/No Remedy
NO Re-install the lamp.
YES Replace the scanning lamp.
YES Replace the DC controller
PCB.
NO Check the wiring from the
DC controller PCB and the
composite power supply
PCB; if normal, replace the
composite power supply
PCB.
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